CHAPTER XXVIII.

_WASTE PRODUCTS AND THEIR DISPOSAL._

The products which are of no direct value to the tanner and currier in the manufacture of leather, and which are nevertheless obtained in fairly large quantities, are of very varying characters. In the present chapter, the most important of them will be described, and some of their uses mentioned.

_Hair_ is removed from the skin of the animal in the process of depilation (p. 143) in the form of a wet sodden mass, containing a considerable amount of lime when the skin has been through the lime-pits.

As white hair is the more valuable, care should be taken in the unhairing to keep it separate from the coloured. It is washed first in plain water to get rid of as much of the lime as possible, and then in water containing a little acid. Hydrochloric acid is often used for this purpose, but sulphurous acid (p. 25) is preferable as it has a slight bleaching action on the hair. The acid neutralises and renders soluble the lime which still remains in the hair, so that it can be easily removed by washing with water. In many tanneries, hair-washing machines are used. The washed hair is dried by laying it out on frames; or preferably, the greater part of the water is first removed by a centrifugal drier, or by pressing, and the drying is completed in a drying room, the temperature of which is a few degrees higher than that of the outside air, and which is provided with a fan or some other appliance for mechanical ventilation. Tables of wire gauze on which the hair is spread, and through which the warm air of the room is drawn by a centrifugal fan, are the most effective.

Coloured hair is sometimes washed and treated like the white hair, but is usually sold direct to plasterers, in which case there is no necessity to remove all the lime and other impurities which the hair contains. A considerable amount of hair is also sold to iron founders, who use it in preparing cores and in loam-casting. The loose lime may be effectively beaten from dried hair by passing it through a disintegrator with one of the grates removed.

_Fleshings and Glue-stuff._--The various scraps of fat and flesh, more or less free from actual hide substance, are usually worked up for glue, though if they cannot be sold for a fair price it will pay to boil them in order to recover the fat they contain. If this is to be done, the fatty portions may be thrown out at the beam and not mixed with the fleshings as in the ordinary way. Before boiling, the fat is treated with sulphurous, sulphuric or hydrochloric acid, sufficient to neutralise the lime present. The boiling should be carried on very gently, so as to allow the fat to rise without emulsifying with the gelatinous matter. For boiling, open steam may be used, but in this case the size formed will have little value; on the other hand, if sulphurous acid has been used and a wooden vat with a copper steam-coil be employed, really good glue may be obtained, and the slight trace of bisulphite which it may contain will prevent its putrefaction. Except under special conditions it will not pay to make glue on a small scale in England, as its value depends much on its appearance, and the necessary plant is somewhat expensive. In some places, however, size can be sold to advantage. Fig. 98 shows a glue-boiling plant.

After separation of the fat by skimming, the clear size is run off from the residual matter into wooden cooling troughs about 5 feet long by 9 inches deep and 15 inches wide, in which it is allowed to set (Fig. 92, p. 425). Great care is required that both size and coolers are quite sweet and free from putrefaction, the coolers being frequently washed with sulphurous acid solution or fresh milk of lime. The jelly is cut out in blocks, and sliced into cakes of appropriate thickness by means of a series of frames like slate-frames which fit over the block of glue, and between which a wire or thin blade stretched on a saw-frame is inserted to cut the glue into sheets. In some factories a machine is used, with a series of parallel blades against which the glue-block is pushed. The sheets are afterwards separated by girls and laid to dry on nets, on which they are frequently turned. When dry, the cakes may be washed with warm water to remove any adhering dirt, but this causes some loss of weight, and in many cases it pays better to dry in a stove until quite hard, then grind in a disintegrator and sell as “size-powder,” in which appearance counts for little if the colour and strength of the size are good.

_Fat._--The fat, whether obtained in the manufacture of glue, or by boiling the fleshings and shavings for its recovery alone, is skimmed from the surface of the heated liquor, and should afterwards be freed from gelatinous matter by washing it with hot water in a tub and running off the upper layer after allowing the water to settle out. The fat thus obtained is a light-coloured grease of buttery consistence.

There are various other sources of waste fats which may be considered here. If glue is made from dried glue-stuff without previous treatment with acid, the fat skimmed off the pans, though dark in colour, will be neutral or alkaline, and a considerable additional quantity of fat and free fatty acids may be obtained by reboiling the “scutch” or refuse with open steam in lead pans with the addition of water and enough sulphuric acid to render the contents of the pan distinctly acid. This grease will be dark and of unpleasant smell from volatile fatty acids, but its odour may be to a considerable extent improved by blowing air and steam through it, and washing with water, or by heating to a temperature somewhat above the boiling-point of water for a considerable time. The same sort of treatment may be applied to the fat pressed out of sheepskins, and to that obtained by boiling currier’s shavings with water and a little acid.

Recovered fats may be separated into a tolerably firm grease suitable for use instead of tallow in currying, and an oil not unlike neatsfoot oil, by melting, allowing to cool slowly to a soupy consistency to promote the crystallisation of the harder fats, and forcing the mixture through flannel cloths in a filter press. The temperature at which the filtration should take place is generally 20-25° C. The oil is, of course, “tender,” or liable to solidify in cold weather; and the more so the higher the temperature at which filtration takes place. The tallow is obtained in cakes. If from fresh fleshings, it will be white and with little odour, but that from dried glue-stuff is usually brown and of unpleasant smell, while recovered grease from curriers’ shavings or “moisings” is always dark in colour.

If the fleshings are to be sold wet, they should be preserved in a sweet lime liquor; if to be dried, they are washed carefully in a fresh lime, spread on frames, and frequently turned over so that they may dry evenly and rapidly. Heat, if employed at all, is in most cases only used at the end of the drying operation, but some tanners dry from the first in a room the temperature of which is a few degrees higher than the normal, and which is provided with good ventilation. For the purposes of the glue manufacturer, the roundings and larger pieces are more valuable than the fleshings, and should be treated with correspondingly greater care by the beamsman and his assistants.

_Bate-Shavings_ are very valuable as sizing materials. They should be well washed in water, or with a very dilute solution of sulphurous acid, and are then laid out in thin layers to dry. They may also be partially dried by pressing between latticed boards in a screw or hydraulic press, and are then best finished as cakes. On the manufacture of sulphurous acid compare p. 25.

_Horns_ are usually kept until the “slough,” “pith,” or internal bone can be knocked out, having become loosened through drying and putrefaction. If kept dry, practically no longer time is required, and the smell and other annoyances incidental to storing in a damp place are avoided. The sloughs may be removed by steaming, but the horns are somewhat damaged by this treatment. The sloughs are principally ground for “bone-meal,” but some are boiled for glue, either without preparation, or after decalcifying with dilute hydrochloric acid.

The actual horn itself, which is quite incapable of making glue, is used chiefly in the manufacture of combs, buttons, and similar articles. The value of horns is to a considerable extent dependent on their size, small horns being unprofitable to work up for the articles above mentioned.

_Spent Tan._--The tan as it is obtained from the leaches after extraction has, naturally, no value for the tanner except as a fuel. Spent tan cannot be profitably sold as manure, as its worth in this respect is extremely small. In those places where white lead is still made by the Dutch process, oak-bark is used to cover up the earthen pots, and commands a good price. It is, however, essential that oak-bark only should be used, as many other tanning materials give off products which injure the colour of the white lead. The quantities of tan used for hot-beds, and for deadening the noise of traffic in the streets, are so small that they are of no practical account in the disposal of this product. Spent tan is not nearly so good as wood for the manufacture of paper, and an attempt to distil it and thereby obtain pyroligneous acid and wood-spirit did not result in any commercial success. On the Continent, fine-ground tan is usually pressed into briquettes for use as domestic fuel, but it would be hard to obtain a market for these in England.

On the whole, in spite of its low heating value, spent tan is best utilised as a fuel. For this purpose specially constructed furnaces are necessary on account of the dampness of the tan, and its low calorific value, which varies, however, with the particular materials: thus while oak-bark and valonia are only poor fuels, hemlock and myrobalans are much better on account of the resin and lignine they contain.

The first successful furnaces for raising steam with wet tan were introduced in the United States, and consisted of large arched combustion chamber with abundant grate-area, and with four or six feed-holes in the fire-brick top which formed a floor on which the spent tan was laid, and where to some extent it was dried by the waste heat. The flames and furnace gases were conducted under the boilers, the flue being very large and deep so as to collect the light ash which was drawn in great quantities from the furnace, and the gases then returned through the tubes of the boiler, afterwards passing down the sides and going to the chimney. The wet fuel was fed in through the firing holes alternately, so that only a part of the grate-space was covered at once with wet fuel; which was speedily ignited by the heat from other parts of the furnace, and especially from the vaulted arch.[187] The large grate-area was a necessity not only on this account, but because of the light weight of the fuel and its low calorific power, which involved the need of burning a large volume. Fig. 99 represents a furnace of similar principle constructed by Messrs. Huxham and Browns. Furnaces of this type are, the author believes, still largely in use in the United States, but in Germany “step-grates” sloping from the furnace-doors towards the back, are now preferred. In these the combustible material rests upon the flat surfaces of the grate, while the air enters by the spaces between the steps without the fuel being able to fall through. Fig. 100 represents the furnace on this principle constructed by the Moenus Co. of Frankfort.

[187] Detailed drawings and particulars are given in Jackson Schultz’s ‘Leather Manufacture in the United States,’ New York, 1876.

The essential conditions which are to be observed in the proper burning of the tan are a sufficiently large grate-area, a correct and sufficient supply of air, and a combustion-chamber of very high temperature. It is consequently not possible to burn tan very successfully in an ordinary Lancashire or Cornish boiler, since not only the grate-space is too limited, but the water of the boiler prevents the upper part of the furnace from attaining a high temperature; and it is therefore difficult to get the damp tan rapidly into vigorous combustion. The difficulty may to some extent be overcome by mixing the tan with a proportion of coal, and by closing the ash-pit and employing a forced draught unless the chimney is a very powerful one. In this way large quantities of tan may be burnt, but without effecting any great saving of coal. The heating power of the tan is improved by the partial removal of its water by pressing, and this is almost essential where a special furnace is not employed.

The answer to the question as to whether tan should be used as fuel in the wet state in which it is obtained from the leaches, or whether it should be previously pressed, depends upon the nature and quantity of the tan. Where abundant quantities of a fairly good material such as hemlock bark are to be disposed of, the cost of pressing is an unnecessary expenditure; but if it is desirable to obtain the highest value from the fuel, or if the furnaces are not well constructed for burning very wet fuels, it will be profitable to press the tan. Hydraulic presses have been used for this purpose, but those now commonly employed consist of powerful rollers arranged in the same way as those of the valonia-crusher (p. 322). The pressure is given by levers loaded with weights or fitted with powerful springs. The liquid which runs from these presses is of little value, as it contains such large quantities of finely divided material that it is almost impossible to filter it, and if run upon the leaches it chokes them and prevents their proper circulation. Much of the cost of pressing is caused by the labour of feeding it to the press, and this may be greatly reduced by the use of mechanical conveyors (p. 325) from the leaches. A tan press is shown in Fig. 101.

_Sewage and other Waste Liquids._--The waste liquors from the different liming, bateing, puering, tanning, washing and other soaking processes are, without any doubt, the most troublesome of any of the side-products which are obtained in the manufacture of leather. In former times they were simply run into the nearest stream, but nowaday the various sanitary authorities and other similar bodies will only permit comparatively pure waters to be turned into a public stream or watercourse.

Various methods of effecting the necessary purification of the waste liquors from tanneries have been proposed at different times, and have been used with varying degrees of success. These methods may be divided into three heads: precipitation, followed by filtration or sedimentation land-treatment; and bacterial purification.

The first of these depends on the power of certain substances, such as alumina and oxide of iron, to carry down organic matter with them if precipitated in solutions containing it. The method usually consists in adding a sufficient quantity of lime to render the waste liquid slightly alkaline, and then treating it with some crude salt of aluminium or of iron. By this means a precipitate of aluminium or iron hydrate is formed, which encloses within itself a considerable proportion of the organic matter of the liquid, and after settling to the bottom of the precipitation-tank is drawn off as “sludge.” Various chemicals are sold under fancy names, such as “alumino-ferric,” “ferrozone,” etc., and have a composition not very dissimilar to that of crude sulphate of iron or alumina. In some cases by-products, such as the acid liquors used in preparing iron articles for “galvanizing,” can be used with advantage.

In the case of the waste liquors from a tannery, the use of these chemicals may often be avoided if sufficient care be taken in regulating the proportion of the various liquids which are to be mixed together and run into the settling tank. As tanning matter combines with lime and dissolved hide-substance to form a heavy brown insoluble precipitate, it is clear that if care be taken to have rather more waste lime-liquor mixed with the waste tan-liquors than is necessary to throw all the tan out of solution, a very considerable amount of purification of the effluent will have taken place without any cost whatever to the tanner. Hence, if the proportion of waste lime is small in comparison to that of the tanning liquors, an extra addition of lime may be necessary in order to precipitate the tannin.

The precipitation- or settling-tanks are usually square or rectangular vessels or pits, the size of which varies with the quantity of liquid to be treated, but the depth of which rarely exceeds six feet. They may be divided into two classes--the “intermittent,” and the “continuous.” In the former class the tank is filled with the mixed waste liquids, taking care that such a sufficiency of lime is present that the mixture is faintly alkaline to phenolphthalein paper, and is then allowed to rest until the suspended matter has settled down to the bottom of the tank, when the clear, or almost clear upper liquid is drawn off, the remainder being the “sludge”; some means must also be employed to prevent the passage of scum and floating matters. In the case of the intermittent process it is advisable to have two tanks, one of which is being filled while the other one is settling or being emptied. With the continuous process the liquids are run into the tank in the proportions calculated to give a maximum amount of purification, as described above, but as they enter very slowly the undissolved matter soon settles, and consequently the liquid may be continuously run out at the further end of the tank. This plan, though it does not yield such good results in the hands of unskilled workmen, is yet useful in many cases, as only one tank is absolutely necessary. It is desirable that in running off the tanks, the effluent should be taken as near the surface as possible, by means of a hinged pipe attached to a float, or some equivalent device; and care is required, as the tank gets low, to avoid the escape of any of the sludge.

For continuous settling the tanks are usually long and somewhat shallow rectangular ponds, into which the previously well-mixed precipitating liquid flows through a wooden trough fixed across one end and as long as the breadth of the tank, and perforated with holes to allow the uniform and quiet influx of the liquid, which finally escapes by a similar trough crossing the opposite end of the tank. In front of the exit-trough a “scum board” must be placed, which is a simple plank dipping slightly below the surface of the liquid, so as to prevent any oil, scum or other floating matter from passing out of the tank along with the clear effluent. Whether the intermittent or continuous system is employed, the effluent should in most cases be afterwards passed through a bacterial filter-bed, or treated by land filtration before it is allowed to flow into a stream or river. Tannery effluents are usually received into sewers without further treatment than mixing and settling to remove solid matter, and many authorities are satisfied with the removal of merely such coarse suspended matters as might choke the sewers. Where continuous precipitation-tanks are used, they must be emptied at frequent intervals, and the sludge run on to cinder-filters, to part with most of its water. These filters are conveniently placed at a lower level than the settling tanks, and it is generally necessary to return the effluent from them for further precipitation and settling. Several types of continuous settling tank with upward flow have been devised by Mr. Candy and others, which are very suitable for use where space is limited; but otherwise less costly constructions are often sufficient. Apart from the question of obtaining an effluent sufficiently good to satisfy the sanitary authority, the treatment of the sludge is one of the greatest difficulties in the purification of effluents. It is usually very bulky, easily putrescible, and therefore difficult to dry; it is of little value for manure; and if allowed to remain long wet, its smell is very offensive.

It has been mentioned that in most cases the liquid, and in every case the sludge, must be freed from solid undissolved matter by filtration. This may take place through open filters or through filter-presses. The open filters generally consist of a pit with an exit at the bottom for the filtered liquid. This pit is filled with either stones and sand, with clinker, ashes or coke. Most tanners use clinker and ashes, as they do not cost anything; and the material should be so arranged that while the lowest layers are very coarse, the surface of the filter-bed should be of the finest material. As soon as this has become covered with so thick a layer of solid matter that the filtration proceeds too slowly, the top surface of the filter may be removed with a rake (taking care to remove as little of the ashes or sand as possible), and burnt, or dried and used as manure. In some cases, filter-presses are used which are composed of grooved or perforated plates with cloths between them through which the liquid is forced by pressure. The solid matter remains behind in the form of a comparatively dry “cake.” The filter-cake, dried if desired, is sold as manure, for which it is in many ways very suitable. Although they work much more rapidly than do the open filters, the cloths so soon become rotten and have to be replaced, that the open ash-filter is on the whole the most convenient for the tanner’s use. It will be readily understood that apparatus of this kind, though very efficient on a small scale, is quite out of the question when many thousand gallons of liquid have to be filtered daily, and so can only be effectively applied to “sludge.”

No system of chemical precipitation has as yet proved entirely satisfactory. Undoubtedly a great deal of purification is effected by this means, but in most cases the “purified” liquid is still too impure to be turned into a stream, though for various reasons this is often permitted by the authorities.

A great advance was made in the purification of effluents when manufacturers were compelled by law to allow the effluent from the precipitation-tank to filter through land set apart for that purpose. In this case certain hardy cereals were sown on the land, which was watered as often as possible with the effluent. This latter, after soaking through the land, was drained off into the nearest stream. Although in many ways this treatment was satisfactory, it had the disadvantage of being very expensive, especially in the neighbourhood of large towns where the price of land is high, and, in addition to this, the conditions necessary for success were far from being correctly understood, so that the land often became “sewage-sick” or waterlogged, and ceased to purify the effluent. It was not until the researches of bacteriologists proved that the purification by land-filtration was mainly due to the bacteria in the soil, that any really satisfactory solution of the problem could be found, but the question has now been to a considerable extent simplified by the introduction of “bacterial treatment.”

Bacteria, considered from the point of view of their action on organic matter, are often classified as “anaerobic” and “aerobic,” though many species are capable of existing under both conditions (Cp. L.I.L.B., Section XXIV.). The anaerobic bacteria thrive only in the absence of air, and their chemical action consists in breaking down the organic matter on which they feed into simpler, and generally more soluble forms, by processes which do not involve oxidation. The aerobic bacteria, on the other hand, require air or oxygen for their existence, and produce changes which are generally of a less complex character, but result in the complete oxidation and conversion of the organic matter to simple compounds, such as nitrates and carbonic acid, which are perfectly harmless and inoffensive. The two classes therefore are to a large extent complementary to each other, the anaerobic bacteria converting the animal or vegetable substances into more soluble and simple compounds which are adapted to the needs of the aerobic, which complete the destruction of the organic matter.

In harmony with what has just been said, bacterial treatment of sewage is of two kinds, each of which may be used alone, or in conjunction with a preliminary precipitation-process, but which are generally best used successively. The oldest form of bacterial purification depends mainly on the action of anaerobic bacteria, and is known as the “septic tank.” This originally consisted of a tank sometimes filled with small pieces of coke, but generally containing the liquid only, and which was tightly closed to prevent access of air and escape of foul gases. It has, however, been found that if deep tanks (6 to 10 feet) are employed, they soon become in continuous use so covered with scum and floating matter as effectually to prevent access of air and light, or any serious escape of smell. The liquid to be purified is allowed to flow very slowly through a tank or series of tanks of this description, entering about a foot below the surface through a distributing trough at one end, and flowing out similarly at the other, at such a rate as to change the contents of the tank about once in twenty-four hours; and when the tank is in working order, the liquid is much purified by the process, and most of the solid organic matter has become liquefied and disappears. It not unfrequently happens, especially where the septic tank treatment is not very prolonged, that the liquid which escapes has a stronger and more offensive odour than it had on entering the tank. It is nevertheless really purer than before, the increased smell being due to the volatile products of the partially decomposed organic matter; and, by passing the liquid through an open coke-filter, the smell will be effectually removed. In all cases it must be borne in mind that as septic tanks and bacterial filters depend for their efficiency on the organisms they contain, time must be allowed for these to develop and accumulate before good results are obtained; and for this about six weeks’ use is generally necessary, after which they will continue to act for an indefinite period until they become choked by sand and inorganic matter.

It must not be supposed that the action in the septic tank is wholly anaerobic; and with weak sewage, most of the organic matter may under favourable circumstances be converted into nitrates and carbonic acid by this means only; but generally a much more complete purification is effected by the subsequent use of “bacterial filters.” These in their simplest form consist of tanks of about 4 feet deep, filled with coke, broken bricks, or clinkers, and fitted with drain pipes at the bottom, by which they can be easily emptied. These tanks, often known as “contact-beds,” are filled with the sewage or septic tank effluent, which is allowed to remain on them two hours, and the tank is then emptied, and allowed a rest of six hours for oxidation and aeration. In most cases the sewage requires two such treatments, the last often through a bed with finer coke, in order to be completely freed from putrescible matter. In place of the intermittent process, as applied on the contact-beds, continuous aerobic filtration is often employed, the bed being so constructed as to allow of free admission of air at the bottom and sides, and the liquid to be purified being distributed on the surface by a sprinkler, or some similar device, and allowed to trickle through the bed. The continuous process seems likely to supersede the intermittent one, as the beds are not only capable of treating a much larger quantity of sewage in proportion to their area, but are also less liable to choke. About six weeks is required, with either contact-beds or continuous filters, before the material they contain becomes coated with the necessary bacterial layer and they get into full working order. The results as regards the effluent are perfectly satisfactory, and the great difficulty and cost consists in the slow but inevitable choking of the beds, which involves the replacement of the porous material. This is considerably delayed by the use of a settled or precipitated sewage, and in this respect, beside its bacteriological function, the septic tank serves a useful purpose in settling insoluble matter, which is much more cheaply removed from it than from the filter-beds. It will be obvious that ordinary settling-tanks, if deep, fulfil many of the functions of the septic-tank, and both lead to the production of a much more uniform liquid from the different effluents which the tanner produces, which is important in the subsequent bacterial purification. A good deal of interesting information on these subjects will be found in a paper by Mr. W. H. Harrison on the ‘Bacteriological Treatment of Sewage.’[188]

[188] Journ. Soc. Chem. Ind., 1900, p. 511.

There are a good many patents in connection with the various methods of sewage purification, and some caution is necessary to avoid their infringement, though of course the general principles of settling and filtration, and the destruction of organic matter by bacterial action, are open to all.

As a general rule the waste-liquors from a tan-yard or leather dye-works are exceedingly impure. They contain the organic matter (in a state of great putrefaction) from the soaks, bates and puers; other organic matter, also more or less putrefied, from the tan-pits; the lime liquors, with their large proportion of lime and of dissolved hide-substance, and in addition the various dyes and other chemicals which may have been used in the conversion of the raw hide into the finished leather; and hence their efficient purification has presented difficulties which do not occur in most other trades.

The different waste liquids are best run into a capacious tank, and, after being thoroughly mixed up together, are allowed to settle for some hours. By this means the greater part of the tanning matter will combine with the lime also present to form a heavy, brown insoluble substance; some of the dye and other organic matter will become entangled in this, and thus be removed from the liquid. The clear liquid is next run off into a bacterial filter (preferably a septic tank, followed by an open coke filter), and then into the nearest stream. If the tannery is near to a town, and the corporation sewers can be utilised, it is probable that a filter made of spent tan may be substituted, as this material will not only remove all excess of lime from the liquid but will also fix much of the colouring matter as well (Koenig). The tan, after being used for this purpose, contains so much lime in its pores that it is said to be useful as manure.

In tanneries where large quantities of disinfectants such as mercuric chloride, carbolic acid, etc., are used, it is necessary that the mixed liquids shall contain so much lime as to make them distinctly alkaline. In this way most of the disinfectants will be either precipitated or rendered inactive. Where arsenic is used in the limes it may be advisable to add a little ferrous sulphate (green vitriol or copperas), in order that the arsenic may form an insoluble compound with the iron, and so be removed along with the sludge. The ink produced by the action of the iron salt on the tan liquors will be completely removed by the bacterial filter.

APPENDICES.

APPENDIX A.

METHOD OF THE INTERNATIONAL ASSOCIATION OF LEATHER TRADES CHEMISTS FOR THE ANALYSIS OF TANNING MATERIALS. INCLUDING ALTERATIONS ADOPTED AT THE LEEDS CONFERENCE IN 1902.

SECTION I.--SAMPLING FROM BULK.[189]

[189] See London Report, pp. 22-29 and 124.

1. _Liquid Extracts._--In drawing samples, at least 5 per cent. of the casks must be taken, the numbers being selected as far apart as possible. The heads must be removed, and the contents mixed thoroughly by means of a suitable plunger, care being taken that any sediment adhering to sides or bottom shall be thoroughly stirred in. All samples must be drawn in the presence of a responsible person.

2. _Gambier and Pasty Extracts._--Gambier and pasty extracts should be sampled from not less than 5 per cent. of blocks, by a tubular sampling tool, which shall be passed completely through the block in seven places. Solid extracts shall be broken, and a sufficient number of portions drawn both from the inner and outer parts of the blocks to fairly represent the bulk. In both cases samples shall be rapidly mixed and enclosed at once in an air-tight bottle or box, sealed and labelled.

3. _Valonia, Algarobilla, Divi-divi, and General Tanning Materials._ Valonia, algarobilla, and all other tanning materials containing dust or fibre, shall be sampled, if possible, by spreading at least 5 per cent. of the bags in layers one above another on a smooth floor, and taking several samples vertically down to the floor. Where this cannot be done, the samples must be drawn from the centre of a sufficient number of bags. While valonia and most materials may be sent to the chemist ground, it is preferable that divi-divi, algarobilla, and other fibrous materials shall be unground. Bark in long rind, and other materials in bundles, shall be sampled by cutting a small section from the middle of 3 per cent. of the bundles with a saw.

4. _Samples for more than one Chemist._--Samples to be submitted to more than one chemist must be drawn as one sample, and well mixed; then divided into the requisite number of portions, not less than three, and at once enclosed in suitable packages, sealed and labelled.

SECTION II.--PREPARATION FOR ANALYSIS.[190]

[190] See London Report, p. 40 _et seq._

1. _Liquid Extracts._--Liquid extracts shall be thoroughly stirred and mixed immediately before weighing, which shall be rapidly done to avoid loss of moisture. Thick extracts, which cannot be otherwise mixed, may be heated to 50° C., then stirred and rapidly cooled before weighing, but the fact that this has been done must be noted in the Report.

2. _Solid Extracts._--Solid extracts shall be coarsely powdered and well mixed. Pasty extracts shall be rapidly mixed in a mortar, and the requisite quantity weighed out with as little exposure as possible, to avoid loss of moisture. Where extracts are partly dry and partly pasty, so that neither of these methods is applicable, the entire sample shall be weighed and allowed to dry at the ordinary temperature sufficiently to be pulverised, and shall then be weighed, and the loss of weight taken into calculation as moisture.

In such cases as gambier, in which it is not possible to grind, or by other mechanical means to thoroughly mix the constituents of the sample, it is permissible to dissolve the whole, or a large portion of the sample, in a small quantity of hot water, and immediately after thorough mixing to weigh out a portion of the strong solution for analysis.

3. _Barks, and other Solid Tanning Materials._--The whole sample, or not less than 250 grms., shall be ground in a mill until it will pass through a sieve of 5 wires per centimetre. Where materials such as barks and divi-divi contain fibrous materials which cannot be ground to powder, the ground sample shall be sieved, and the respective parts which do and do not pass through the sieve shall be weighed separately, and the sample for analysis shall be weighed so as to contain like proportions.

SECTION III.--PREPARATION OF INFUSION.

1. _Strength of Solution._--The tannin solution employed shall contain from 0·35 to 0·45 grms. per 100 c.c. of tanning matters absorbed by hide. (Paris 1900.)

2. _Solution of Liquid Extracts._--A sufficient quantity shall be weighed into a covered basin or beaker, from which it shall be washed into a liter flask with boiling water and well shaken, and the flask shall be filled to the mark with boiling water. The neck being covered with a small beaker, the flask shall be placed under a cold water tap or otherwise rapidly cooled to a temperature between 15° and 20° C., and made up accurately to the mark, after which it shall be thoroughly mixed, and the filtration at once proceeded with.

_Note._--Tannin infusions may be kept from fermenting by the addition of 3 to 5 drops of essential oil of mustard per liter. (F. Kathreiner.)

3. _Filtration._--The filtration of the solution for analysis may take place through any paper which may be considered most suitable for the particular case, and with or without the use of kaolin, absorption of tanning matter, if any, being corrected for by an amount determined by a similar filtration of a clear solution. Perfectly clear solutions need not be filtered.

To determine the correction, about 500 c.c. of the tanning solution of the strength prescribed for analysis is obtained perfectly clear, preferably by the method of filtration which is to be corrected for. After thorough mixing, 50 c.c. is evaporated to determine “total soluble No. 1.” A portion of the remainder is then filtered in the manner for which correction is to be made, and 50 c.c. of the filtrate is evaporated for “total soluble No. 2.” Deducting No. 2 from No. 1 the difference is the correction required, which must be added to the total soluble found by analysis. It is generally advisable, both in analysis and in the second filtration for correction, to filter first 150 c.c. (which in analysis may be used for the determination of non-tannins), and then to employ the next 50 c.c. for evaporation, keeping the filter full during the operation; but whatever procedure is adopted must be rigidly adhered to in all analyses to which the correction is applied. Where kaolin is employed, a constant weighed quantity (1 or 2 grm.) must be used, which is first washed with 75 c.c. of the liquor by decantation, and then washed on to the filter with a further quantity of liquor, of which 200 c.c. is filtered as above.[191]

[191] It is obvious that in the first instance it will be necessary to determine the correction for each particular material employed, but it will soon be found that the correction is practically constant for large groups of tanning materials, so long as the same method of filtration is rigidly adhered to.

4. _Solid Extracts._--Solid extracts shall be dissolved by stirring in a beaker with boiling water, the undissolved portions being allowed to settle, and treated with further quantities of boiling water, and the solution poured into a liter flask. After the whole of the soluble matter is dissolved, the solution is treated similarly to that of a liquid extract.

5. _Extraction of Solid Materials._--Such quantities shall be weighed as will give an infusion of the strength already prescribed. (_Preparation of Infusion_, Resolution 1.) Not less than 500 c.c. of the infusion shall be extracted at a temperature not exceeding 50° C., after which the temperature shall be gradually raised to 100° C.,[192] and the extraction continued till the percolate is free from tannin and the whole made up to one liter, the weaker portions of the solution being first concentrated if necessary by evaporation in a flask, in the neck of which a funnel is placed.

[192] In substances which, like canaigre, contain a large quantity of starch, the extraction should be completed at a temperature of 50° C.--H. R. P.

SECTION IV.--DETERMINATION OF TANNING MATTERS AND NON-TANNINS; ETC.

1. _Total Soluble Matter._--100 c.c.[193] of the clear filtered tanning solution, or a smaller quantity if the balance employed is of sufficient delicacy, shall be evaporated in an open weighed basin of platinum, hard glass, porcelain, or nickel, on the water-bath, and the basin shall afterwards be dried till constant in an air-oven, at a temperature of 100° to 105° C., or at a temperature not exceeding 100° C. _in vacuo_ till constant, care being taken that no loss occurs by splintering of the residue. The use of the vacuum-oven for drying the residues is recommended when possible.

[193] 50 c.c. is sufficient, and is the quantity now generally employed.

2. _Determination of Non-Tannins._--That the filter method shall remain the official method until the next Conference, but that members be permitted to employ the chromed hide-powder method of the American Association of Official Agricultural Chemists of 1901 (Appendix C) where it is desired, the fact being clearly stated on the report that the A.O.A.C. method has been employed, and not that of the I.A.L.T.C. (Leeds, 1902, see note, p. 480.)

That the “bell form”[194] of filter, as described by Professor Procter, shall be employed; not less than 5 grms. of hide-powder be used; the hide-powder should be so packed in the tube that the detannised liquor shall come over at a rate of about one drop in two seconds; and the filtrate be rejected so long as it gives a turbidity with a clear tanning solution. The filtrate may be used for the determination of non-tannin so long as it gives no reaction with salted gelatine solution.[195] The first 30 to 35 c.c. should be thrown away, and the next 50 c.c. of detannised solution, or an aliquot part of it, evaporated in a weighed basin on a water bath, and then dried till constant in an air-oven at a temperature of 100° to 105° C., or, _in vacuo_, not exceeding 100° C.

[194] It is obvious that the exact form and dimensions of the filter must be adapted to the character of the hide-powder available, as considerable differences exist in the absorptive power of different samples.

[195] 8 to 9 grams of good gelatine are dissolved in 500 c.c. of hot water, 100 grams of salt added, and the whole cooled and filtered.

3. _Hide-Powder._--That the hide-powder must be sufficiently absorbent for use in the filter, and that in a blank experiment conducted with distilled water in the same way as an analysis, the residue from the evaporation of 50 c.c. should not exceed 5 milligrams.

The Freiberg Hide-Powder, made by Mehner and Stransky, containing between 10 and 20 per cent. of cellulose (as suggested by Cerych), is recommended by the Conference (Liège, 1901) and is very suitable for the filter method; but the powder, when analysed by the Kjeldahl method and calculated to 18 per cent. of moisture, must not contain less than 11·5 per cent. of nitrogen (Leeds, 1902).

4. _Determination of Moisture and “Total Dry Matter.”_--That the moisture in the sample be determined by drying a small portion at the temperature adopted in the determination of the “total soluble.” In extracts yielding turbid solutions which can be thoroughly mixed, it is generally preferable after mixing the solution and before filtration, to measure off and evaporate 50 c.c. for the determination of total dry matter (and moisture) in the same manner as the “total soluble.”

5. _Statement of Results._--It is recommended, when full analysis is given, that the Statement should be made in the following manner:--

(1) _Tanning Matters Absorbed by Hide._--Obtained by deducting the “soluble non-tanning matters” found by evaporating the hide-powder filtrate from the “total soluble.”

(2) _Soluble Non-Tanning Matters._--Found by evaporation of filtrate from hide-powder filter.

(3) _Insoluble._--By deducting “total soluble matter” from the “total dry matter.”

(4) _Moisture._--Determined by drying a portion at the temperature adopted in the determination of “total soluble.”

If other determinations are given they shall form a separate additional statement.

_Density._--The statement of densities of extracts, etc., should be given as specific gravity in preference to arbitrary degrees, such as Baumé, Twaddell, etc.

SECTION V.--COLOUR MEASUREMENT.

_Colour Measurement._--It is recommended that the method used by English chemists, namely, measuring with Lovibond’s Tintometer (as described by Professor Procter and Dr. Parker, Journ. Soc. Chem. Ind., 1895, 125), shall be used, and the results stated in units of red, yellow and black. The measurement may be made on the solution used for analysis, but must be calculated to one containing 0·5 per cent. of tanning matter, in a centimetre cell.

ANALYSIS OF USED LIQUORS.

It was decided at Liège, 1901, and Leeds, 1902,[196] that the “Shake Method” with chromed hide-powder, of the American Association of Official Agricultural Chemists, 1901 (A.O.A.C.), should be employed in the detannisation of used tanning liquors, as with these the filter method is apt to give too high results owing to the amount of non-volatile acids which they contain. The method of the A.O.A.C. is given in Appendix C.

[196] Procter and Blockey quoted experiments at the Leeds Conference, proving that gallic acid and some other non-tanning substances were largely absorbed by the hide-powder filter, though probably not permanently retained by leather; while the error, though still considerable, was much less when the chromed hide-power shake method was employed. Where only gallotannic and gallic acids are present, as in the case of sumach and commercial gallotannic acids, the most accurate quantitative estimation is probably that by the Löwenthal method carried out as described L.I.L.B., p. 123, but considerable skill is required in its execution.

ANALYSIS OF SPENT TANS.

It was decided at Leeds, 1902, that spent tans must be analysed like fresh tanning materials; but where the prescribed strength of solution cannot otherwise be obtained it is permissible to concentrate the entire solution by evaporation. It is advisable, where suitable apparatus is available, to concentrate _in vacuo_; but failing this, an ordinary flask may be used, in the neck of which a funnel is placed.

APPENDIX B.--THE DECIMAL SYSTEM.

The metrical system of weights and measures, and the Centigrade thermometer scale have been generally used throughout the book, as more international and scientific than the complicated systems still unfortunately in use in this country. They have been fully explained in the Author’s ‘Laboratory Book,’ p. 2; but as this is not always at hand, a short sketch may be permitted here.

The basis of the metrical system is the “meter,” which is approximately ¹⁄₁₀,₀₀₀,₀₀₀ of the distance from the earth’s pole to the equator, and is equal to 39·3708 English inches, and for many practical purposes may be roughly reckoned as 40 inches. The meter is divided into 10 parts or “decimeters,” 100 parts or “centimeters,” and 1000 parts or “millimeters.” The standard of capacity is a cube of 1 decimeter, or about 4 inches, and consequently contains 1000 cubic centimeters, and is denominated a “liter.” The standard of weight is 1 cubic centimeter of water (at 4° C.), which is called a “gram.” Hence 1 liter of water weighs 1 “kilogram,” or 1000 grams. 1 cubic meter of water contains 1000 liters, and weighs 1000 kilograms, or 1 metrical ton (2200 lb. English). For purposes of reduction, the following figures may be given:--

1 gram = 15·431 grains. 1 lb. av. = 453·6 grams.

1 liter = 0·22 gallon. 1 gallon = 4·543 litres.

Actual reduction is, however, generally unnecessary if the question be treated as one of proportion. Thus a solution of 1 gram per liter is of the same strength as one of 1 lb. per 100 gallons (1000 lb.), and very approximately, as one of 1 oz. avoirdupois per cubic foot. In the case of pits, it is often simplest to measure them directly with a meter rule; length, breadth and depth, measured in decimeters and multiplied together, giving the contents in liters, and, in the case of water, the weight in kilograms.

The Centigrade or Celsius thermometer divides the difference between the freezing and the boiling points of water into 100°. The following table gives the points at which its scale agrees without fractions with that of Fahrenheit:

COMPARISON OF CENTIGRADE AND FAHRENHEIT DEGREES.

°C. °F. -20 -4 -15 +5 -10 14 -5 23 0 32 5 41 10 50 15 59 20 68 25 77 30 86 35 95 40 104 45 113 50 122 55 131 60 140 65 149 70 158 75 167 80 176 85 185 90 194 95 203 100 212 105 221 110 230 115 239

APPENDIX C.

OFFICIAL METHOD FOR ANALYSIS OF TANNING MATERIALS, ADOPTED AT THE EIGHTEENTH CONVENTION OF THE AMERICAN ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS, 1901.

I. PREPARATION OF SAMPLE.

Barks, woods, leaves, dry extracts, and similar tanning materials should be ground to such a degree of fineness that they can be thoroughly extracted. Fluid extracts must be heated to 50° C., well shaken, and allowed to cool to room-temperature.

II. QUANTITY OF MATERIAL.

In the case of bark and similar material, use such quantity as will give about 0·35 to 0·45 gram tannins per 100 c.c. of solution, extract in Soxhlet or similar apparatus at steam-heat for non-starchy materials. For canaigre and substances containing like amounts of starch use temperature of 50° to 55° C., until near complete extraction, finishing the operation at steam-heat. In case of extract, weigh such quantity as will give 0·35 to 0·45 gram tannins per 100 c.c. of solution, dissolve in 900 c.c. of water at 80° C., let stand twelve hours, and make up to 1000 c.c.

III. MOISTURE.

(_a_) Place 2 grams, if it be an extract, in a flat-bottom dish, not less than 6 cm. in diameter, add 25 c.c. of water, warm slowly till dissolved, continue evaporation and dry.

(_b_) All dryings called for, after evaporation to dryness on water-bath, or others, shall be done by one of the following methods, the soluble solids and non-tannins being dried under similar, and so far as possible identical conditions:

1. For eight hours at the temperature of boiling water in a steam bath.

2. For six hours at 100° C., in an air bath.

3. To constant weight _in vacuo_ at 70° C.

IV. TOTAL SOLIDS.

Shake the solution, and without filtering immediately measure out 100 c.c. with a pipette, evaporate in a weighed dish, and dry to constant weight, at the temperature of boiling water. Dishes should be flat-bottomed, and not less than 6 cm. in diameter.

V. SOLUBLE SOLIDS.

Double-pleated filter paper (S. and S., No. 590, 15 cm.) shall be used. To 2 grams of kaolin add 75 c.c. of the tanning solution, stir, let stand fifteen minutes, and decant as much as possible. Add 75 c.c. more of the solution, pour on filter, keep filter full, reject the first 150 c.c. of filtrate, evaporate the next 100 c.c. and dry. Evaporation during filtration must be guarded against.

VI. NON-TANNINS.

Prepare 20 grams of hide-powder by digesting twenty-four hours with 500 c.c. of water, and adding 0·6 gram chrome alum in solution, this solution to be added as follows. One-half at the beginning and the other half at least six hours before the end of the digestion. Wash by squeezing through linen, continue the washing until the wash-water does not give a precipitate with barium chloride. Squeeze thoroughly by hand, and remove as much water as possible by means of a press, weigh the pressed hide, and take approximately one-fourth of it for moisture determination. Weigh this fourth carefully and dry to constant weight. Weigh the remaining three-fourths carefully and add them to 200 c.c. of the original solution; shake ten minutes, throw on funnel with cotton plug in stem, return until clear, evaporate 100 c.c. and dry. The weight of this residue must be corrected for the dilution caused by the water contained in the pressed hide-powder.[197] The shaking must be done in some form of mechanical shaker. The simple machine used by druggists, and known as the milk-shake, is recommended.

[197] For method of correction, see p. 313.

PROVISIONAL METHOD.--To 14 grams of dry chromed hide-powder in a shaker glass add 200 c.c. of the tannin solution, let stand two hours, stirring frequently, shake fifteen minutes, throw on funnel with a cotton plug in the stem, let drain, tamp down the hide-powder in the funnel, return the filtrate until clear and evaporate 100 c.c.

VII. TANNINS.

The amount of these is shown by the difference between the soluble solids and the corrected non-tannins.

VIII. TESTING HIDE-POWDER.

(_a_) Shake 10 grms. of hide-powder with 250 c.c. of water for five minutes, strain through linen, squeeze the magma thoroughly by hand; repeat this operation three times, pass the last filtrate through paper (S. and S. No. 590, 15 cm.) till clear, evaporate 100 c.c. and dry. If this residue amounts to more than 10 mg. the hide must be rejected.

(_b_) Prepare a solution of pure gallo-tannin by dissolving 6 grams in 1000 c.c. of water. Determine the total solids by evaporating 100 c.c. of this solution and drying to constant weight. Treat 200 c.c. of the solution with hide-powder exactly as described in paragraph 6. The hide-powder must absorb at least 95 per cent. of the total solids present. The gallo-tannin used must be completely soluble in water, alcohol, acetone and acetic ether, and should not contain more than 1 per cent. of substances not removed by digesting with excess of yellow mercuric oxide on steam-bath for two hours.

IX. TESTING NON-TANNIN FILTRATE.

(_a_) _For Tannin._--Test a small portion of the clear non-tannin filtrate with a few drops of a 1 per cent. solution of Nelson’s gelatin. A cloudiness indicates the presence of tannin, in which case repeat the process described under VI., using 35 instead of 20 grams of hide-powder.

(_b_) _For Soluble Hide._--To a small portion of the clear non-tannin filtrate add a few drops of the filtered tannin solution. A cloudiness indicates the presence of soluble hide, in which case repeat the process described under VI., giving the hide-powder a more thorough washing.

The temperature of solutions shall be between 16° and 20° when measured or filtered. All dryings should be made in flat-bottomed dishes of at least 6 cm. diameter, S. and S. No. 590, 15 cm. filter paper should be used in all filtrations.

APPENDIX D.

The following Lists of Colours have been furnished by Mr. M. C. Lamb, Director of the Leather Dyeing Department of Herold’s Institute, London, who has devoted much time to testing the various dyes with regard to their permanence and suitability for leather. Many of the colours have also been tested and found satisfactory in the Leather Department of the Yorkshire College. The following abbreviations of makers’ names are used in the lists:--

B. BASLER CHEMISCHE FABRIK, A. G. Basle, Switzerland. B.A.S.F. BADISCHE ANILIN UND SODA FABRIK. Ludwigshafen a. Rhine, Germany. Ber. BERLIN ANILINE CO. Berlin S.O., Germany. B.S. Spl. BROOKE, SIMPSON & SPILLER. Atlas Dye Works, Hackney Wick, London, N.E. By. FARBEN-FABRIKEN, late BAYER & CO. Elberfeld, Germany. C. L. CASSELLA & CO. Frankfort a. Main, Germany. C.A. FRENCH ANILINE COLOUR WORKS. Vieux-Conde (Norde), France. C. & R. CLAUS & RÉE. Clayton, near Manchester. D. DAHL & CO. Barmen, Germany. D. & H. DURAND, HUGUENIN & CO. Basle, Switzerland. G. R. GEIGY & CO. Basle, Switzerland. Ger. GERBER & CO. Basle, Switzerland. K. KALLE & CO. Bierbrich a. Rhine, Germany. Leon. A. LEONHARDT & CO. Muhlheim a. Main, Germany. Leitch J. W. LEITCH. Milnsbridge Chemical Works, Huddersfield. Lev. LEVINSTEIN LTD. 21 Minshull Street, Manchester. M.L.B. MEISTER, LUCIUS & BRUNING. Hoechst a. Main, Germany. Mo. GILLIARD, P. MONNET & GARTIER. Lyons, France. N. NOETZEL, ISTEL & CO. Griesheim a. Main, Germany. O. K. OEHLER & CO. Offenbach a. Main, Germany. P. ST. DENIS DYESTUFF CO., late POURIER. St. Denis, near Paris. R. SOCIÉTE CHIMIQUE DES USINES DU RHONE. Lyons, France. R. H. & S. READ, HOLLIDAY & SONS. Huddersfield. S.C.Ind. SOCIETY OF CHEMICAL INDUSTRY. Basle, Switzerland. Uer. CHEMISCHE FABRIKEN. Uerdingen a. Rhein, Germany. W. Bros. WILLIAMS BROS. & CO. Hounslow, Middlesex.

STAINING.

SINGLE ACID DYES SUITABLE FOR STAINING VEGETABLE TANNED LEATHER.

_Browns._

Solid brown. (M.L.B.) Acid brown. (W. Bros.) Brown A2. (B.S. Spl.) Brown A1. (B.S. Spl.) Mikado brown B. (Leon.) New acid brown. (B.S. Spl.) Bronze acid brown. (By.) Golden brown Y. (C.), (By.) Acid anthracene brown R. (By.) Fast brown N. (B.A.S.F.) Nut brown A. (C.) Fast brown. (By.) Fast brown G. (Ber.) Resorcin brown. (Ber.) Resorcin brown. (D.) Acid brown. (Ber.) Dark nut brown. (W. Bros.) Acid brown R. (C.) Acid brown R. (Uer.) Acid brown R. (R. H. & S.) New golden brown A1. (C.) Dark brown. (C.) Acid brown L. (B.A.S.F.) Acid brown D. (C.)

_Yellows._

Azo yellow. (Uer.) Phosphine subst. (B.S. Spl.) Chrysoine. (W. Bros.) Azo-acid-yellow. (Ber.) New phosphine G. (C.) Cuba yellow 2072. (S.C. Ind.) Cuba yellow (W. Bros.) Azo-flavine RS. (C.) and (B.A.S.F.) Azo-flavine 3R. (B.A.S.F.) Indian yellow R. (By.) Turmeric yellow. (G.) Solid yellow G. (Leon.) Solid yellow B. (Leon.) Indian yellow R. (C.) Cuba yellow. (C.) Napthol yellow S. (By.), (C.), (B.A.S.F.) Turmeric yellow. (C.), (G.) Fast acid yellow. (C.A.)

_Reds and Oranges._

Scarlet R. (By.) Crocein scarlet 3BN. (By.) Orange 2. (M.L.B.), (S.C. Ind.), (C.) and (B.A.S.F.) Orange 2B. (By.) Mandarin G extra. (Ber.) Brill. crocein M.O.O. (C.) Bordeaux G. (By.) Atlas orange. (B.S. Spl.) Bordeaux cov. (Ber.) Fast red 21528. (By.) Fast red A. (Leon.), (By.), (Ber.), and (B.A.S.F.) Bordeaux B. (M.L.B.)

_Greens._

Acid green extra conc. (C.) Guinea green B. (Ber.) Guinea green G. (Ber.) Acid green GG. (By.) Acid green BB. (By.) Acid green B. (By.) Acid green G. (By.) Acid green 000. (Leon.) Acid green extra. (By.) Acid green (Uer.) Acid green (R. H. & S.) Light green SF. (B.A.S.F.) Erioglaucine. (G.)

_Violets._

Acid violet 4RS. (Ber.) Acid violet 7B. (Ber.) Acid violet 6B. (By.) Formyl violet S4B. (C.)

_Blues._

Bavarian blue D.B. (Ber.) Marine blue o. (K.) Solid blue. (M.L.B.) Blue 1. (Lev.) Blue 2. (Lev.) Blue 3. (Lev.)

SINGLE BASIC DYES SUITABLE FOR STAINING VEGETABLE TANNED LEATHER.

_Browns._

Bismark brown GG. (C.) Chrysoidine AG. (O.) Bismark brown 2B. (K.) Bismark brown (By.) Bismark brown R.C.E. (Lev.) Bismark brown M. (By.) Vesuvine conc. (M.L.B.) Vesuvine conc. (B.A.S.F.) Bismark brown C extra. (Leon.) Bismark brown RS. (B.S. Spl.) Bismark brown 3762. (W. Bros.) Rheonine A. (B.A.S.F.) Rheonine N. (B.A.S.F.) Brown R. (G.) Brown G. (G.) Manchester brown. (C.)

_Yellows._

Acridine yellow NC. (Leon.) Phosphine N. (Ber.) Patent phosphine R. (S.C. Ind.) Leather yellow 6730. (C.A.) Auramine 2. (By.) Chrysoidine cryst. (B.S. Spl.) and (By.) Chrysoidine diamond cryst. (W. Bros.) Leather yellow o. (M.L.B.) Chrysoidine. (R. H. & S.) Leather yellow G. (M.L.B.) Leather yellow 6730. (C.A.) Patent phosphine G. (S.C. Ind.) Leather yellow DRR. (Ber.) Xanthine. (O.) Cannella G. (W. Bros.) Pure phosphine. (C.) New phosphine G. (C.) Cori-phosphine o. (By.) Para-phosphine R. (C.) Para-phosphine G. (C.) Leather yellow 374. (D.) Leather yellow 375. (D.) Homo-phosphine G. (Leon.) Phosphine ABN. (Leon.) Auramine 2 patent. (S.C. Ind.)

_Greens._

Methyl green cryst. (Ber.) Methylene green. (M.L.B.) Solid green. (Leon.) Malachite green. (Ber.), (M.L.B.), (P.), (C.A.), (S.C. Ind.), (R. H. & S.), (Lev.), (C.), (B.S. Spl.) and (K.)

_Reds._

Safranine. (M.L.B.), (B.A.S.F.), (S.C. Ind.) and (K.), (Ber.), (By.), (C.A.), (Leon.), (Uer.) Russian Red. (By.) and (Ber.)

_Violets._

Methyl violets. (Ber.), (By.), (M.L.B.), (R. H. & S.), (B.S. Spl.), (C.) (S.C. Ind.), (P.) and (D.).

_Blacks._

Corvoline B. (B.A.S.F.) Corvoline G. (B.A.S.F.)

DYEING.

SINGLE ACID COLOURS SUITABLE FOR DYEING VEGETABLE TANNED LEATHERS.[198]

[198] For explanation of Roman numerals see end of Appendix D.

_Yellows._

II. Napthol yellow S. (Ber.), (B.A.S.F.), (By.) and (C.). VII. Quinoline yellow. (Ber.), (By.) and (B.A.S.F.). II. Citronine. (Leon.) IV. Solid yellow G. (Leon.) IV. Solid yellow B. (Leon.) V. Indian yellow S. V. Azo-acid yellow. IV. Indian yellow T. (C.) VII. Indian yellow R. (By.) and (C.). IV. Indian yellow G. (By.) and (C.). IV. Cuba yellow. (C.), (W. Bros.) and (S.C.Ind.). V. Azo-flavine RS. (B.A.S.F.) and (C.). V. Azo-flavine 3R. (B.A.S.F.) and (C.). VI. Circumein extra. (Ber.) VII. Tartrazine. (B.A.S.F.)

_Oranges._

V. Orange 2. (B.A.S.F.), (C.), (M.L.B.), (S.C. Ind.), (P.) (W. Bros.) and (By.). V. Mandarin G extra. (Ber.) V. Crocein orange. (K.) and (By.). VI. Ponceaux 10RB, 4R, Bo, 4RB, 6RB. (Ber.), (By.) and (D.).

_Bordeaux._

VII. Azo bordeaux. (By.) IV. Bordeaux B extra. (By.) VI. Bordeaux G. (By.) V. Bordeaux Y. (W. Bros.) V. Acid maroon. (M.L.B.) and (B.S. Spl.). VIII. Chromatrop 6B. (M.L.B.)

_Reds._

V. Fast red A. (Ber.), (By.), (B.A.S.F.), (B.S. Spl.) and (Leon.) VIII. Fast red S. (M.L.B.) VI. Fast red 21528. (By.)

_Scarlets._

V. Crocein scarlet R. (By.) and (K.). V. Crocein scarlet 2R. (By.) VII. Fast scarlet B. (B.A.S.F.), (W. Bros.) and (K.)

_Browns._

IV. Acid brown R. (C.) V. Acid brown L. (B.A.S.F.) V. Acid brown Y. (S.C. Ind.) IV. Acid brown D. (C.), (B.A.S.F.) IV. Acid brown (R.H. & S.) IV. Acid brown 4601. (B.S. Spl.) V. Acid brown D. (C.) VII. Resorcin brown. (Ber.) V. Acid brown. (Uer.) IV. Acid brown R. (Ber.) VIII. Acid brown Y. (M.L.B.). VI. Solid brown o. (M.L.B.) V. Fast brown. (By.) V. Fast brown. G. (Ber.) V. Fast brown. N. (B.A.S.F.) IV. Fast brown. 3B. (Ber.) V. Bronze acid brown. (By.) VIII. Acid anthracine brown R. (By.) V. New acid brown. (B.S. Spl.) VI. Dark nut brown. (Uer.) IV. New golden brown A1. (C.)

_Blacks._

IV. Napthol blue black. (C.) V. Napthylamine black 4B. (C.) V. Napthylamine black 6B. (C.) VII. Phenol black S. (By.) IV. Phenylamine black 4B. (By.) VII. Victoria black B. (By.)

_Blues._

VIII. Fast blue R. (Ber.) VIII. Bavarian blue DB. (Ber.) V. Erioglaucine. (G.) IV. Cyanole ext. (C.) IV. Marine blue. (K.) VII. Water blue N. (B.A.S.F.) VIII. Water blue 4 B. (Ber.) VII. Cotton blue II. (By.). VII. Toluidine blue. (B.A.S.F.) and (By.). VII. Water blue R. (Leon.) VII. Water blue 3R. (Leon.) VII. Water blue BTR. (B.A.S.F.)

_Violets._

Acid violets (Lev.), (B.A.S.F.) and (By.) IX. Acid violets 4R. (B.A.S.F.) V. Acid violets R. (C.) V. Acid violets R. (B.A.S.F.) VI. Acid violets 3BA. (M.L.B.) IV. Acid violets 3BN. (Lev.) II. Acid violets 6B. (By.) and (C.). III. Formyl violet S4B. (C.)

_Greens._

IV. Acid green extra conc. (C.) IV. Guinea green B and G. (Ber.) IV. Acid green ext. (By.) IV. Acid green GG ext. (By.) IV. Acid green 225. (By.) IV. Acid green BB. ext. (By.) IV. Acid green o. (M.L.B.) IV. Acid green 5677. (B.S. Spl.) V. Capri green 2G. (Lev.)

SINGLE BASIC DYES SUITABLE FOR DYEING VEGETABLE TANNED LEATHERS.

_Browns._

IV. Vesuvine ooo ext. (B.A.S.F.) II. Vesuvine B. (B.A.S.F.) II. Vesuvine (C.) III. Vesuvine conc. (M.L.B.) III. Bismark brown ext. (Ber.) and (B.S. Spl.). III. Bismark brown ext. M. (By.) III. Bismark brown F. (By.) IV. Bismark brown YS. (B.S. Spl.) III. Bismark brown PS. (C.) III. Bismark brown GG. (C.) III. Bismark brown O. (L.) III. Bismark brown G. (O.) III. Bismark brown (S.C. Ind.) III. Bismark brown NYY. (W. Bros.) III. Bismark brown o. (M.L.B.) II. Cannella. (B.S. Spl.) II. Cannella. (B.A.S.F.) II. Cannella. (C.) V. Cannella. (S.C. Ind.) II. Cannella S. (Ber.) III. Cannella P. (W.) IV. Nanking. (B.A.S.F.) IV. Nanking. (R.H. & S.) IV. Nanking. (S.C. Ind.) III. Lavilliere’s 122. (By.) II. Rheonine. (B.A.S.F.) IV. Xanthine. (O.)

_Yellowish Oranges._

III. Chrysoidines, (Leitch); R, (R.H. & S.) IV. Chrysoidines ext. (W.). II. Chrysoidines (S.C.Ind.); GG,(C.) III. Chrysoidines G. (Leon.) II. Chrysoidines RE. (Lev.) III. Chrysoidines YY. (C.) III. Chrysoidines cryst. (B.S. Spl.) III. Chrysoidines G. (By.) V. Chrysoidines cryst. (C.A.)

_Yellows._

III. Auramine 2. (B.A.S.F.) III. Auramine. (S.C. Ind.) III. Auramine. (G.) III. Auramine. (Ber.) III. Auramine. (By.) III. Auramine. (L.) III. Auramine. (W.) III. Auramine. (C.) III. Auramine. (W.) V. Auramine conc. (M.L.B.). IV. Phosphine E. (B.A.S.F.) IV. Phosphine L. (B.A.S.F.) IV. Phosphine G. (Ber.) IV. Phosphine. (O.) IV. Phosphine. (C.) IV. Phosphine Ext. (M.L.B.) IV. Phosphine B ext. (S.C. Ind.) III. Phosphine III., II., I. (Leon.) III. Phosphine N. (Ber.). V. Cori-phosphine. (By.) V. Homo-phosphine. (Leon.) V. Para-phosphine. (C.)

_Greens._

III. Methyl green cryst. (By.) D. V. Methylene green o. (M.L.B.) II. Diamond green B and G. (B.A.S.F.) II. Benzal green. (O.) II. Brillt. green cryst. (M.L.B.) II. Brillt. green cryst. (By.) II. Brillt. green cryst. (O.) II. Brillt. green cryst. (L.) II. Brillt. green cryst. (Lev.) II. Brillt. green cryst. (Uer.) II. Brillt. green cryst. (S.C. Ind.) II. Malachite green. (B.S. Spl.) II. Malachite green. (Ber.) II. Malachite green. (C.A.) II. Malachite green. (K.) II. Malachite green. (M.L.B.) II. Malachite green. (Lev.) II. Malachite green. (G.) II. Malachite green. (O.)

_Blues._

VII. Methylene blue B, 2B and R. (Ber.) VII. Methylene blue. (B.A.S.F.) VII. Methylene blue. (M.L.B.) VII. Methylene blue. (Lev.) VII. Methylene blue. (C.) VII. Methylene blue. (C. & R.) VIII. New methylene blue. GG. (C.) VIII. New methylene blue. BB. (C.) IV. New blue R. (Ber.) V. New blue R. (By.) VI. New patent blue 4B. (By.)

_Violets._

IV. Methyl Violet 4B. (B.A.S.F.) IV. Methyl Violet 4R. (K.) IV. Methyl Violet 4R. (C.) IV. Methyl Violet 3B. (By.) IV. Methyl Violet 3B. (Ber.) IV. Methyl Violet 2B. (M.L.B.) IV. Methyl Violet (D.) IV. Methyl Violet 6B. (Leon.) IV. Neutral violet ext. (C.)

_Bordeaux._

IV. Magenta WB. (Leon.) IV. Magenta 3B. (Ber.) IV. Magenta RE. (Leon.) IV. Magenta WBG. (Leon.) IV. Magenta. (M.L.B.) IV. Magenta. (K.) IV. Magenta. (B.A.S.F.) IV. Magenta 4128. (B.S. Spl.)

_Reds._

VIII. Rhodamine B extra. (Ber.) VIII. Rhodamine B. (B.A.S.F.) VIII. Rhodamine B. (By.) VIII. Rhodamine (S.C. Ind.) VIII. Rhodamine (M.L.B.) VII. Safranine. (B.A.S.F.) IV. Russian red G. (B.A.S.F.). IV. Russian red B. (C.) IV. Russian red (Ber.) IV. Russian red (Uer.) IV. Russian red B. (B.A.S.F.) IV. Russian red G. (C.) IV. Russian red (Ber.) IV. Russian red R. (By.) IV. Cardinal 4B. (By.) VIII. Rhoduline red. (By.) V. Safranine G ext. (C.) VII. Safranine BS. (By.) Safranine G ext. (Ber.)

ACID MIXTURES SUITABLE FOR DYEING AND STAINING VEGETABLE TANNED LEATHERS.

Orange 2. (M.L.B.) Azo-yellow o. (M.L.B.) Patent blue V. (M.L.B.)

Resorcin brown. (Ber.) Circumein ext. (Ber.) Nigrosine 105. (Ber.)

Acid brown R. (C.) Indian yellow G. (C.) Pure soluble blue. (C.)

New acid brown. (B.S. Spl.) Phosphine subst. (B.S. Spl.) Induline. (B.S. Spl.)

Acid brown R. (C.) Azo-flavine R.S. (C.) Naphtol blue black. (C.)

Resorcin brown, (Ber.) Fast brown G. (Ber.) Napthylamine black D. (C.)

Fast brown G. (Ber.) Circumine ext. (Ber.) Nigrosine 105. (Ber.)

Fast brown. (By.) Indian yellow R. (By.) Fast green blue shade. (By.)

Acid anthracene brown. (By.) Indian yellow R. (By.) Fast green blue shade. (By.)

Fast brown N. (B.A.S.F.) Azo-flavine RS. (B.A.S.F.) Light green S.F. (B.A.S.F.)

Dark nut brown. (Uer.) Azo-yellow. (Uer.) Acid green. (Uer.)

Acid brown. (D.) Crocein orange. (D.) Cotton blue 3R. (D.)

Resorcin brown. (D.) Cotton blue 3R. (D.)

Acid brown B. (S.C. Ind.) Cuba yellow 2072. (S.C. Ind.) Acid green. (S.C. Ind.)

Resorcin brown. (W. Bros.) Cuba yellow. (W. Bros.) Acid green. (W. Bros.)

Napthol brown. (Leon.) Citronine A. (Leon.) Acid green 000. (Leon.)

Acid brown R. (R.H. & S.) Acid yellow. (R.H. & S.) Nigrosine cryst. (R.H. & S.)

Orange 2. (P.) Yellow oS. (P.) Acid green J3E. (P.)

Acid brown. (C.A.) Acid yellow S. (C.A.) Pure blue cryst. (C.A.)

Resorcin brown. (Ber.) Azo-acid-yellow or Circumine ext. (Ber.) Bavarian blue DB, or Guinea green G. (Ber.)

Indian yellow R. (C.) Acid brown R. (C.) Pure soluble blue. (C.)

Azo-acid-yellow conc. (M.L.B.) Solid brown o. (M.L.B.) Fast blue o sol. (M.L.B.)

Bronze acid brown. (By.) Indian yellow R. (By.) Fast green blue shade. (By.)

Acid anthracene brown. (By.) Indian yellow R. (By.) Fast green blue shade. (By.)

Orange 11. (B.A.S.F.) Scarlet GL. (B.A.S.F.) Light green SFYS. (B.A.S.F.)

Azo-flavine RS. (B.A.S.F.) Acid brown L. (B.A.S.F.) Light green SFYS. (B.A.S.F.)

Chocolate. (Uer.) Tartrazine, (B.A.S.F.); or Azo-yellow, (Uer.)

BASIC MIXTURES SUITABLE FOR DYEING AND STAINING VEGETABLE TANNED LEATHERS.

Bismark brown M. (By.) Auramine 2. (By.) Methylene blue BB. (By.)

Rheonine A. (B.A.S.F.) Vesuvine B2. (B.A.S.F.) Diamond green G. (B.A.S.F.)

Bismark brown O. (Leon.) Auramine 2. (Leon.) Solid green P. (Leon)

Bismarck Brown ext. (Ber.) Philadelphia yellow R. (Ber.) Malachite green cryst. (Ber.)

New phosphine G. (C.) Chrysoidine. (C.) New blue B. (C.)

Phosphine ext. (F.) Chrysoidine diamond cryst. (F.) Bright green cryst. ext. (F.)

Bismark brown GG. (O.) Aniline yellow ext. (O.) Neutral violet ext. (O.)

Dark brown B. (By.) Auramine 2. (By.) Emerald green cryst. (By.)

Phosphine 3RB. (Ber.) Philadelphia yellow R. (Ber.) Russian green 36784. (Ber.)

Bismark Brown RS. (B.S. Spl.) Cannella. (B.S. Spl.) Malachite green. (B.S. Spl.)

Vesuvine conc. (M.L.B.) Auramine conc. (M.L.B.) Methylene green. (M.L.B.)

Cutch brown. (Leitch.) Lemon yellow G. (Leitch.) Russian green 3 B. (Leitch.)

Bismark brown 2 B. (K.) Yellow for leather ext. (K.) Malachite green cryst. (K.)

Auramine. (G.) Brown R. (G.) Malachite green. (G.)

Auramine o. (Lev.) Bismark brown R.C.E. (Lev.) Brill. green. (Lev.)

Bismark brown Y40. (R.H. & S.) Canary 2. (R.H. & S.) Green cryst. Y. (R.H. & S.).

Leather brown A. (S.C. Ind.) Auramine 2. (S.C. Ind.) Leather black 1. (S.C. Ind.)

Leather black R. (Uer.). Yellow 4803. (Uer.) Blue black S. (Uer.)

Bismark brown NYY. (W. Bros.) Cannella G. (W. Bros.)

Brown for leather 375. (D.) Fast yellow 168. (D.) Methyl green G ext. fine. (D.)

Brown N. (D.) Leather brown P. (D.) Paris violet o. (D.)

CHROME LEATHER.

The following dye-stuffs are suitable for dyeing chrome leather. The leather after tanning, is boraxed in the usual manner and then mordanted by drumming or paddling in a tannin solution; for dark shades 3 per cent. gambier and 3 per cent. fustic extract (the weight being calculated on the leather struck out after boraxing) is suitable; for light shades 1¹⁄₂ per cent. gambier is to be recommended. The leather, after mordanting, is fat-liquored and dyed, adding a weight of sodium or potassium bisulphate equal to that of the dye-stuff, to the dye-bath. The following is not by any means a complete list of the dyes which will dye chrome leather well, but merely representative.

After the goods are dyed, they should be well washed in tepid water to which has been added a little common salt; one pound to every three dozen skins being a suitable amount to use. When the goods have been washed, they are struck out by machine and are then ready for shaving, if the operation has not been performed previous to dyeing. The skins are afterwards nailed out flat, grain-side up, on boards, and a mixture of glycerine and water--3 lb. of glycerine dissolved in one gallon of water being a suitable strength--is well sponged on the grain-side; the goods are now lightly oiled (using a good sperm, neat’s-foot or mineral oil), before being taken to the drying room. When thoroughly dry they are taken off the boards, and placed with layers of damp sawdust between each skin, for a few hours in order to allow the goods to become suitably damp for staking. The skins should now be well staked by machine, the Haley (England), Slocomb or Vaughn (America) being good machines for this purpose (p. 192).

After staking, the goods are “soft-boarded,” and a thin coat of a weak linseed mucilage is applied to the skins, which are afterwards dried out and seasoned with the following mixture:--

“Soak 10 to 15 oz. of dry egg albumen for four hours in 1 gallon of cold water, with occasional stirring, strain off any insoluble matter and add 1 gallon of milk. A little carbolic acid (phenol) may be added to the above if it is desired to keep the finish for more than two or three days--1 oz. of phenol previously dissolved in a little water, added to each gallon of the finish, being a suitable amount.” A little dye should be added to the mixture.

After seasoning, the skins are dried out in the stove, glazed twice round and re-seasoned with the above mixture diluted with its own volume of water. The goods are dried out and again glazed, perched lightly, and finally boarded up from neck to tail in order to raise the popular straight-grain. Should the glaze be too bright the albumen solution may be reduced to half-strength.

When the goods have been glazed they are rubbed over on the grain side with a flannel cloth which is slightly damp with linseed oil, trimmed up, and are ready for sale.

DYES SUITABLE FOR DYEING CHROME-TANNED LEATHER.

_Browns._

Resorcin brown. (Ber.) Chocolate. (Uer.) Fast brown. (BY.) Fast brown. (Ber.) New golden brown A.1. (C.) Fast brown. (B.A.S.F.) Acid brown Y. (S.C. Ind.) Acid brown B. (S.C. Ind.) Golden brown. (Leitch.) Bronze acid brown. (By.) Light nut brown. (Uer.) Resorcin brown. (W. Bros.) Acid brown 5210. (W. Bros.) New acid brown. (B.S. Spl.) Light nut brown. (R.) Brown 2Y. (R.) Azo-phosphine. (Uer.) Golden brown Y. (W. Bros.)

_Yellowish Browns and Yellows._

Citronine. (Leon.) Azo-flavine RS. (B.A.S.F.) Cuba yellow 2072. (S.C. Ind.) Phosphine substitute. (B.S. Spl.) Azo-yellow conc. (M.L.B.) Azo-flavine. (R.) Golden orange R. (Leitch.) Circumein ext. (Ber.) Indian yellow G. (By.) Turmeric substitute (W. Bros.). Azo-yellow R. (M.L.B.). Chrysophenin G. (Leon.) Indian yellow T. (C.) Quinoline yellow. (Ber.) Cuba yellow. (C.) and (W. Bros.) Indian yellow. G. (C.) Chrysoine ext. (W. Bros.) Azo-flavine. (B.S. Spl.) Turmeric yellow B. (Leitch.) Azo-yellow FY. (R.H. & S.) Orange 4. (R.H. & S.) Naphtol yellow S. (B.A.S.F.) Turmeric yellow Y. (Leitch.) Azo-flavine 7032. (S.C. Ind.) Turmeric yellow. (G.) Solid yellow Y. (Leon.) Solid yellow B. (Leon.) Milling brown G. (Leon.) Napthamine yellow 3 G. (K.) Orange GG. (C.) Resorcin yellow. (Ber.)

_Greens._

Acid green conc. (M.L.B.) Acid green ooo. (Leon.) Guinea greens G and B. (Ber.) Acid green ext. conc. (C.) Fast acid green BN. (C.). Erioglaucine. (G.) Acid green 5677. (W. Bros.) Acid green (Uer.) Light green SF. (B.A.S.F.) Acid green ext. GG. (By.)

_Violets and Blues._

Bavarian blue DB. (Ber.) Blue R. (Lev.) Water blue TR. (B.A.S.F.) Fast blue O. (M.L.B.) Water blue 4B. (Leon.) Cyanole extra. (C.) Acid blue. (C.A.) Acid violets 3BN and 6BN. (Lev.)

_Oranges._

Orange 2, (S.C. Ind.); C, (M.L.B.); B, (By.) and (B.A.S.F.). Orange A. (Leon.) Orange G. (R.H. & S.) Ponceaus. (Ber.) and (By.) Crocein oranges. (K.) and (By.) Mandarine G ext. (Ber.) Atlas oranges. (B.S. Spl.)

_Scarlets and Reds._

Most acid scarlets and reds dye chrome leather well on the mordant, particulars of which are given above.

_Blacks._

These are dyed direct without any mordanting.

Leather black V. (By.) Leather black 1. (S.C.Ind.) Naphthylamine blacks 4B and 6B. (C.) French black. (Uer.) Chrome leather black. (C. & R.) Coomassie black 4BS. (Lev.) Phenylamine black 4B. (By.)

Titanium salts (potassium titanium oxalate and tanno-titanium oxalate) may be employed in conjunction with the coal-tar colours for dyeing chrome leather, with many advantages over the ordinary mordants, the colour produced being faster to light, rubbing, fuller in shade, and with much less tendency to “grinning.” When employing titanium mordants, the leather should be first lightly mordanted with some tannin solution and afterwards dyed with the titanium and dye-stuff in the same bath, in which case only “acid” dyestuffs may be employed. If desired the goods may be mordanted with the tannin mordant, afterwards treated with the titanium salts, washed and dyed; in this case the dyeing and application of the titanium mordant being carried out separately, the leather may be dyed with either the acid or basic dye stuffs. The titanium and tannin mordants may also be applied in the same bath.

DYEING CHAMOIS LEATHER.

The following colours dye chamois leather well, after washing the leather in a weak soda solution, mordanting with 3 per cent. basic chrome alum solution, and transferring to the dye-bath without washing. Equal weight of bisulphate of soda to that of the dyestuff is added to the dye-bath.

BASIC COAL-TAR COLOURS.

Bismark brown extra. (Ber.) Philadelphia yellow R. (Ber.) Pure phosphine. (C.) Leather blue V. (G.) Leather brown Y. (S.C. Ind.) Leather brown A. (S.C. Ind.) Philadelphia brown. (Ber.)

ACID COAL-TAR COLOURS.

Circumine extra. (Ber.) Resorcin brown. (Ber.) Induline NN. (B.A.S.F.) Orange 2. (M.L.B.) Golden brown. (Leitch.) Fast brown. (By.) Azo-yellow R. (M.L.B.) Napthylamine black 4B. (C.) Chocolate. (Uer.) Azo-flavine RS. (C.) Azo-phosphine. (Uer.) Acid anthracene brown R. (By.) Acid green conc. (M.L.B.) Acid brown Y. (S.C. Ind.) Acid brown B. (S.C. Ind.) Napthylamine black 4B. (O.) Jet black cryst. (C.) Anthracene brown R. (By.) Anthracene brown GG. (By.) Anthracene brown W. (By.) Dark nut brown. (Uer.) Orange 2. (M.L.B.)

NATURAL DYESTUFFS.

Peachwood extract. Sapan ext. Logwood ext. Fustic ext. Turmeric ext.

A variety of shades may be obtained on chamois leather by mordanting in a 1 per cent. solution of the titanium salts above mentioned and then transferring without washing to the dye-liquor, which is best used in the drum. The colours which are most suitable are the Alizarin colours, Janus colours and the natural dyestuffs.

_Alizarin Colours._

Alizarin black produces light slate. Alizarin orange „ bright orange. Alizarin blue „ blue. Azo-alizarin black „ brownish maroon. Azo-alizarin brown „ reddish violet. Alizarin red „ bright scarlet red. Azo-alizarin blue „ slate blue. Coerulein „ yellowish green. Azo-alizarin yellow „ bright yellow. Anthracene brown „ fawn brown. Acid anthracene brown G „ brownish orange. Acid anthracene brown R „ dull chocolate brown. Anthracene blue „ pale blue. Mordant yellow „ lemon yellow.

_Janus Colours._

Janus yellow G. produces bright orange. Janus yellow R. „ reddish orange. Janus red „ dark maroon. Janus claret red „ bluish maroon. Janus brown R. „ dark reddish chocolate. Janus blue B. „ bluish black.

_Natural Dyestuffs._

Barwood produces salmon pink. Logwood „ dull reddish brown. Fustic „ bright yellow. Turmeric „ yellow. Brazil wood „ reddish brown. Sapan wood „ light nut brown. Sumach „ buff yellow. Persian berries „ light orange yellow. Madder „ red. Quercitron bark „ light orange yellow. Cutch „ fawn brown. Campeche „ canary yellow. Peach wood „ pale reddish tint. Divi-Divi „ buff yellow.

The leather is run in the dyestuff solution at a temperature of about 45° to 50° C. for about half an hour, and then lightly fat-liquored, if desired, and afterwards dried.

In addition to the dyestuffs mentioned above many basic colours may be employed after the treatment with titanium, some of these producing a colour lake with the titanium mordants.

As regards the permanency of the various colours to light, the reader is referred to an important paper by Mr. Lamb,[199] but in many cases the probable permanency is indicated by a number prefixed to the name of the colour in Roman figures, I. corresponding to the lowest, and X. to the highest permanency. In the research referred to, about 1500 samples of leathers dyed with coal-tar dyes were exposed to light for a series of “periods,” each equal in actinic power to nine days of the brightest summer sunshine. The most fugitive colours faded completely, even in the first “period,” and the most permanent before the end of the tenth. The prefixed numerals indicate to which of these “periods” the colour survived.

[199] Journal of Society of Chemical Industry, 1902, p. 156.

INDEX.

_Abies_, 246 _Acacia_, 288 -- _arabica_, 165 Acetic acid, 154, 221, 410 Acid, acetic, 154, 221, 410 -- amido-acetic, 61 -- -- -caproic, 61 -- -- -propionic, 61 -- -- -succinic, 61 -- arsenious, 26 -- aspartic, 61 -- benzoic, 29 -- boric, 155, 162, 221, 229 -- butyric, 61 -- carbolic, 26, 295 -- carbonic, 99, 105, 161 -- chromic, 200 -- cresotinic, 29, 162 -- digallic, 295 -- ellagic, 231, 296 -- ellagitannic, 231, 297 -- formic, 154, 159, 410 -- gallotannic, 295 -- hydrochloric, 154, 157 -- lactic, 154, 158, 221 -- linolenic, 355 -- oleic, 240, 354, 360 -- oxalic, 155, 221 -- oxynaphthoic, 30, 163 -- perchromic, 200 -- protocatechuic, 295 -- pyroligneous, 154 -- salicylic, 28, 295 -- stearic, 351 -- sulphuric, 114, 154, 157, 410 -- sulphurous, 23, 114, 338 -- xanthoproteic, 67 Acids, action on hide, 84 -- amido-, 61, 66 -- in tanning liquors, 20 -- mineral, 23 -- use in softening, 114 Acrilene bating acid, 163 Adipose tissue, 53 _Æthalium septicum_, 10 African oak, 257 Ageing, 188 _Ailantus_, 272 Air, capacity for moisture, 426 -- cost of heating, 428 -- -filters, 439 -- -passages, 437 -- weight of, 428 Alanine, 61 Albumin of hide, 65 Albumins, 56, 66 Alcohol, action on hide, 83 Alcoholic fermentation, 13, 16 Alder, 250 Allen, 366 Aleppo pine, 248 Algarobilla, 286, 293 Alizarine colours, 403 Alkalies, action on gelatine, 89 -- -- on hide, 84 Alkaline carbonates, 138 _Alnus_, 250 Alsop, 313 Alum, 159, 339, 185 Alumed leathers, 2, 4, 9 -- -- dyeing, 402 Alumina, 185 -- in water, 103 -- soap, 352 Aluminium, 185 Amido-acetic acid, 61 -- -acids, 61, 66 -- -caproic acid, 61 -- -propionic acid, 61 -- -succinic acid, 61 Amines, 173 Amœba, 10 Ammonium chloride, 157, 159 -- sulphate, 159, 184 Analysis of tanning materials, 300, 475, 482 _Anacardiaceæ_, 269 Andreasch, 272 Angicabark, 293 Anhydrides of tannins, 297 Aniline dyes, 394 Anion, 80 _Anogeissus_, 293 Anticalcium, 29, 157 Antiseptics, 21 A.O.A.C. method, 300, 312, 482 _Apocynaceæ_, 279 Apples of Sodom, 261 Arata, 269 Arbutus, 279 Archbutt and Deeley, 95 _Arctostaphylos_, 279 Arsenic, 26 -- cures, 39, 42 -- -limes, 194 -- sulphide, 139, 142 Arsenious acid, 26 Aspartic acid, 61 _Aspidospermum_, 279 Association of Official Agric. Chem., 300, 312, 482 Atmospheric pressure, 422 Attractions of molecules, 74 Avidity of acids, 81 Azo-colours, 399

Bablah, 289 Babool, 165, 228, 288 Babul--_see_ Babool _Bacillus erodiens_, 175 _Bacteria_, 14, 15 -- aerobic and anaerobic, 471 Bacterial filters, 469, 472 -- products, 18, 19 _Bacterium furfuris_, 166 Badamier bark, 282 Bag-tannage, 235 Bakau bark, 283 Balance, analytical, 310 Balaustines, 285 Bali-babilan, 288 _Balsamocarpon_, 286 Band-knife splitting machine, 384, 387 _Banksia_, 268 Barbed wire scratches, 43 Barium chloride, 391 -- sulphydrate, 142 Bark, 243, 244 Bark mills, 316, 452 Barytes, 390 Basic chrome liquors, 211, 241 -- salts, 187, 199 Bast, 243 Bastin, 244 Bate-shavings, 463 -- -stains, 176 Bating, 8, 19, 152, 170, 233 -- effect of water on, 107 Baudouin’s test, 365 Bearberry, 279 Becker, 172, 174 Bedda nuts, 282 Beeswax, 371 Beetle attacking hides, 42 “Bell”-mills, 317 Belting, 450 Benzene, 295 Benzoic acid, 29 Bernardin, 242 Betel nut, 248 _Betula_, 250 _Betulaceæ_, 250 Bichromate of potash, 201 Biernacki, 21 Bilberry, 280 Birch, 250 -- -tar oil, 32 Bistort, 266 Bisulphites, 25, 338 Biuret reaction, 67 Black-dyeing, 398, 399, 413 Bleunard, 57 Blood-albumen, 337 Bloom, 231, 297 Bluebacking, 217 Boarding, 233 Boiler incrustations, 99, 101 Boiling point, 75, 421 Bone-oil, 62 Book-binding leathers, 234 Boral, 155 Borax, 156, 216 Borgman, 181 Boric or boracic acid, 156 Bottle-tannage, 235 Bourgois, 57 _Brabium_, 268 Bran-drench, 166, 195 Brands, 43 Brazil-wood, 287, 413 Breaking stress of leathers, 451 Breed, effect on skin, 45 Brick pits, 455 Brining hides, 38 Briquettes of tan, 464 Bronzing, 395, 404 Brunton, 61 Brusca, 272, 280 Brushing machine, 226 Buff-leather, 378 “Buffalo” method, 129 Burns and Hull, 163 _Butea_, 285 Butyric acid, 61 _Byrsonima_, 269

C. T. bate, 163 Calcium sulphydrate, 140 Calculation of tannin analysis, 314 Calf-kid, 189 Calorie, 422 _Cambium_, 243 Camphor, 31 Canaigre, 264 -- root, extraction, 348 Carbolic acid, 26, 295 Carbolineum, 28 Carbon disulphide, 30 Carbonic acid, 99, 105, 161 Carboxyl, 295 Carr’s disintegrator, 319 Carter’s disintegrator, 319 Cascalote, 286 Casein, 68 Cassia, 235, 287, 299 _Castanea_, 251 _Casuarina_, 249 Catechins, 298 Catechol, 295 -- tannages, 234, 295 Catechu, 277, 289 Caustic alkalies, 22 -- soda, 114, 136 Cavallin, 202 Cavallo, 285 Cebil, 293 Cells, 10 Cellulose, 12 Centigrade thermometer, 481 Centrifugal pumps, 458 _Ceriops_, 283 Chain-conveyors, 325, 453 Chamois leather, 9, 378 -- -- dyeing, 496 Chamoising, 369, 378 Chemical deliming, 153 Chenailier evaporator, 424 Chestnut, 251 -- -oak, 254, 263 -- -wood extract, 222, 231 Chlorides in water, 104 Chondrin, 63 Chromalin, 212 Chrome-alum, 201 -- -blacks, 402 -- combination tannages, 215 -- -iron ore, 200 -- leather, 4, 9 -- -- dyes for, 494 -- tannages, 200 Chromic acid, 200 Chromium, 185, 200 Churco bark, 280 Clark, 95 _Cleistanthus_, 293 Coal-tar or C. T. bate, 29, 163 -- -- dyes, 394 _Coccoloba_, 267 _Cocos_, 249 Cockle, 45 _Cæsalpinia_, 285 Coffee-mill, 317 Cohn’s solution, 177 Colloids, 77, 396 Colour, theory of, 416 -- -measurement, 479 Colouring matters, 299 Colours, primary, 416 -- secondary, 416 -- tertiary, 416 Combination-tannages, 4, 236 _Combretaceæ_, 280, 293 Concentration of extracts, 339 Concrete pits, 455 Cone-mill, 317 _Coniferæ_, 246 Connective tissue, 50 _Conocarpus_, 283 Contact-beds, 472 Conveyors, 325, 327, 453 Copper in water, 104 -- sulphate, 26 _Coriariaceæ_, 277 _Coriaria_, 272, 277 _Corium_, 46 Coriin, 64 Cork, 244 _Cork-cambium_, 243 Cork oak, 257 Corrosive sublimate, 25 _Cortegia rossa_, 248 Couperus, 277 Creasote, 28 Creolin, 28 Cresotinic acid, 29, 162 Crown leather, 381 Crystallisation, 77 Crystalloids, 77 _Cupuliferæ_, 251 Curtidor bark, 280 Curupy bark, 293 Cutch, 289 Cuticle, 46 _Cutis_, 46 Cylinder-oils, 100

Danish glove-leather, 236, 238 _Daphne_, 267 Daphnoidæ, 267 Decoloration of extracts, 337 Degrees of hardness, 94, 105 Dégras, 368, 380 “Dégras-former,” 370, 385 Deliming by acids, 154 -- by washing, 154, 160 De Lof, 242 Denaturised salt, 23 Dennis, 163, 211 Depickling, 91 Depilation, 7, 54, 119 Depletion by puers and bates, 91 _Derma_, 46 _Dermestes vulpinus_, 42 “Devil disintegrator,” 318 Dextrose, 16 Diazo-compounds, 399 Digallic acid, 295 Diffusion, 78 Dippel’s oil, 62 Disc-mill, 317 Disinfectants, 21, 474 Disintegrators, 318 Dissociation, 85 Distilled grease, 359 Divi-divi, 285 Djaft, 263 Docks, 264 Dog-dung, 174, 179, 181 “Dogskin,” 197 Dongola, 197 -- imitations, 241 -- leather, 236, 239 Doornbosch, 293 Drench fermentation, 19 Drenching, 8, 20, 152, 166, 195, 233 _Drepanocarpus_, 285 Dressing-leather tannage, 232 -- leathers, 8 Driers for oils, 363 Drum-stuffing, 388 Drumming, 234 Drums, 117 Dry hides, 110 Drying, effect on skin, 112 -- hides, 41 -- leather, 424 -- oven, 308 -- rooms, 431 -- of sole leather, 232 Dry-salted hides, 110 -- -salting, 38 Dschigh dschighe, 286 Dubbing, 386 Dust-prevention, 325 Dye-testing, 419 Dyeing alumed leathers, 402 -- chrome leather, 403, 493 -- Continental method, 408 -- defects in, 404 -- in drum, 408 -- in paddle, 407 -- in tray, 406, 408 -- kid, 196 -- oil-leathers, 404 -- selection of goods, 409 -- theories of, 396 Dyes, acid, 395, 412 -- basic, 395, 411 -- lists of, for leather, 486, _et seq._ -- list of manufacturers, 485 -- mixtures for leather, 491 -- -woods, 412

Earp, W. R., 143 East India skins, 235, 238, 241 Eberle, 212 Edge-stones, 316 Effluents, 467 Egg-albumin, 67 -- -yolk, 68, 393 Eglinton Tanning Co., 203 Egyptian leathers, 2 _Einbrennen_, 390 Eitner, 105, 109, 112, 114, 131, 168, 205, 212, 216, 252, 366, 382, 392 Elandsboschjes, 293 Elastic fibres, 53, 69 Electric driving, 449 Electrolytes, 79 Electrolytic dissociation, 79 _Elephantorrhiza_, 293 Ellagic acid, 231, 297 Ellagitannic acid, 231, 297 Emulsifying, 240 Enzymes, 15, 16, 171, 173 _Epidermis_, 46, 68 _Epithelium_, 46 -- -cells, 13 _Erector pili_, 50 _Ericaceæ_, 279 “Erodin,” 174 Espinillo, 293 Essential oils, 31 _Eucalyptus_, 284 Eudermin, 27 _Euphorbiaceæ_, 293 Evaporation, 421 -- for analysis, 307 -- in _vacuo_, 423 Evaporator, Yaryan, 339 Evergreen oak, 256 Excise-duties on leather, 3 Extraction, _optimum_ temperature, 344 Extracts, liquid, analysis, 301, 305, 475, 476, 477 -- solid, analysis, 301, 305, 476, 477 -- use of, 342

Fading of colours, 405 Fahrion, 61 Faller-stocks, 116 Fan, Blackman, 428, 430, 434 -- Capel, 437 -- centrifugal, 437, 439 -- drying by, 433 -- screw, 430, 434, 437 Fat, 461, 462 -- -cells, 52 -- -glands, 48 -- -liquoring, 217, 237, 239, 393 -- -liquors, 100 -- -tanned leathers, 1, 4 Fats and oils, 350 -- solvents of, 353 Fatty acids, liquid, 354 -- -- saturated, 354 -- -- unsaturated, 355 Fellmongering, 34 Fermentation, 13, 15 Ferric chloride, 86 -- salts, 198 Ferrocyanides, 339 Ferrous salts, 198 Fibre-bundles, 50 Fibres, elastic, 53 Fibrils, 50 _Filao_ bark, 249 Filter method, 311, 478 Filtration for analysis, 307, 477, 483 -- of sludge, 470 “Fine-hairing,” 180 Finishes for leather, 401 Fire insurance, 325 Fish-tallow, 368 Flaying, 42 Fleshing, 8, 146 -- machines, 147 Fleshings, 461 Flückiger and Hanbury, 277 Fluorides, 26 “Foots,” 356 Formaldehyde, 30, 380 Formalin, 31, 380 Formic acid, 154, 159, 410 Frizing, 378 _Fuchsia_, 284 Fuchsine, 395 Fungi, 15 _Fusanus_, 267

Gall oak, 261 Gallotannic acid, 295 Galls, 261, 280 Gambier, 222, 231, 277 -- extraction, 349 _Garcinia_, 293 Gas-engine, 449 -- -lime, 141 Gaseous state of matter, 74 _Gaultheria_, 251, 373 Gelatin, 56, 58 -- action of bacteria on, 61 -- analyses, 57 -- chemical constitution, 57 -- decompositions, 60 -- determination, 59, 60 -- properties of, 58 -- reactions, 62 -- swelling of, 82 Glaeser mill, 318 Glassy layer, 50, 398 Glazing, 418 Globulin, 67 Globig, 17 Glove-kid, 194 Glucose, 13, 16, 177, 390 Glue, 461 Gluestuff, 461 Glutin, 56, 58 Glycerin, 351 “Golden spoon,” 269 -- tan bark, 248 Gonagra, 264 Grain, 233 -- “drawn,” 228 -- -layer, 51 -- microscopic examination, 52, 55 -- pattern of, 52 Grains of various skins, 52 _Granataceæ_, 285 Grease, recovery, 462 -- refining, 463 Greases, 357 “Green leather,” 197, 239 _Grevillia_, 268 Griffith, 231 Grinding machinery, 452 -- samples, 303, 476 Grounding, 189 Guano, 177 Gum tree, 284 Gumming, 20 _Guttiferæ_, 293 _Gunnera_, 284 _Gunneraceæ_, 284 Glycocine, 61 Glycocoll, 61

_Hæmatoxylon_, 286 Hair, 68, 460 -- -bulb, 49 -- -cuticle, 48, 49 -- -muscle, 50 -- -papilla, 49 -- structure and growth, 47 Hand-stuffing, 386 Handlers, 221 Hardness determination, 94 -- effect on dyeing, 100 -- effects on tanning, 98, 105 -- of water, 93 Harrison, 273, 473 Hauff, 157, 162, 163 Heal, 203 Heat, capacity for, 422 -- consumed in evaporation, 423, 428 -- -- in melting ice, 423 -- given by pipes, 432 -- loss through walls, 431 -- measure of quantity, 422 -- of combustion of coal, 423 Heating by hot water, 442 -- by steam, 432, 436, 440 Heath honeysuckle, 268 Heaths, 279 Hehner, 94 Heinzerling, 203 Helvetia leather, 381 Hemicollin, 60 Hemlock-bark, 222 Hen-dung, 179, 181 Henry, 95 “Hickory” bark, 291 Hide-fibre, analysis, 57 -- -markets, 33 -- -mill, 117 -- powder, 310, 312, 479, 484 -- -- filter, 311, 478 -- -- chromed, 313, 483 High-speed machinery, 451 Hofmeister, 56, 57, 60 Holbrook system, 331 Holden fat, 359 Horns, 464 Horn-sloughs, 464 Horny structures, 50 Horse-fat, 357 -- -flesh, 177 -- -power, 423 Hruschau, 214 Hull, 163, 165 Hummel, 203, 250, 285 Hunt, 188 Hyaline layer, 50, 176, 398 Hydrochloric acid, 86, 154, 157 Hydronaphthol, 30 _Hypoderma bovis_, 43 Hyposulphite of soda, 204 _Hyphæ_, 14

I.A.L.T.C. method, 300, 311, 475 Ice, heat to melt, 423 Ilex, 256 Immiscible liquid, 76 _Inga_, 293 Inks, 402 “Inoffensive,” 143 International Association of Leather Trade Chemists, 300, 311, 475 Internal pressure of liquids, 76 Invertase, 16 Iodine-value, 353 Ionisation-pressure, 81 Ions, 80 Iron-alum, 199 -- -bark tree, 284 -- -blacks, 398, 413 -- in water, 102 -- stains, 22, 38 -- tannages, 198 Izal, 28

Jamrosa bark, 282 Japans, 355 Jeye’s fluid, 28 Jellies, 77 Jensen, 241 Jones fleshing machine, 148 Juniper, 248

Kaspine leather, 380 Kath, 289 Kathreiner, 301 Kation, 80 Kent, 236 Keratin, 14, 56, 68 Kermes oak, 258 Kid-leather, 9 Kilogram, 481 Kips, soaking, 113 Kjeldahl’s method, 70, 179 Klemm, 381 Knapp, 74, 188, 199, 202, 210, 382 _Knoppern_, 262 Knotted tree, 268 Koch, 251 Koerner, 82, 91, 283 _Krameria_, 269

Lace-Leathers, 197 Lactic acid, 154, 158, 221, 410 -- fermentation, 18 Lamb, 218, 273, 405, 485 Land filtration, 470 Lanoline, 359 Lanosoap, 218 Larch, 247 _Larix_, 247 _Lauraceæ_, 267 Layers, 222, 231 Leach-bottom, 329 Leaching, 328 Lead-bleach, 399 -- in water, 104 Leather Industries Laboratory Book, 5 _Leguminosæ_, 288 Leidgen unhairing machine, 145 Lentisque, 269 _Leucadendron_, 268 Leucine, 61 _Leucospermum_, 268 Levulose, 16 Lewkowitsch, 366 Lietzmann, 382 L.I.L.B., 5 _Liliaceæ_, 248 Lime, 21, 120 -- action on hide, 125 -- analyses, 124 -- “available,” 125 -- -burning, 121 -- -liquors, analysis, 143 -- pits, 127, 455 -- quantity used, 129 -- solubility in water, 123 -- -water, 123 Limes, age of, 130 -- bacterial action in, 134 -- plumping, 133 Liming, 126 -- loss of hide-substance, 132 -- Pullman’s method, 137 -- sheep-skins, 34 -- temperature, 129 Linolenic acid, 355 Lipowitz, 59 Liquor-pipes, 456 Liquid state of matter, 74 Liquor tanks, 332, 457 -- -troughs, 333, 457 Liter, 481 Logwood, 286, 413, 398, 401 _Loxopteryngium_, 269 Lubrication, 453 Lufkin, Prof., 142 Lymph corpuscules, 10 Lysol, 28

McFadyen, 61 Madder, 239, 277 Maiden, 290 Magenta, 395 Magnesia, 95 _Malpighia_, 269 _Malpighiaceæ_, 269 Manganese, 185 _Mangifera_, 277 Mangle, 283 Mango, 277 Mangosteen, 293 Mangrove, 283 -- bark, extraction, 348 Mangrutta, 269 Market-hides, 33, 108 “Marking off,” 406 -- weight of hides, 33 Marsh Rosemary, 268 Mather and Platt, 97 Mauve, 394 Maynard, 114 “Mellowing” of liquors, 82 Mellowness of liquors, 229 Mercuric chloride, 25 -- iodide, 26 Metabisulphite of soda, 25, 114, 160 Meter, 481 Metrical system, 481 Milk-shaker, 313 Millon’s reagent, 67 Mill for samples, 303 Mills, arrangement of, 452 -- construction, 316 Mimosa, 231, 290 -- extraction, 346 _Mimoseæ_, 288 Mineral acids, 23 Moellon, 368, 380 Moisture in tanning materials, 314, 315, 479, 482 Molecules, 74 Mordant colouring matters, 238 Mordants, 398 Moulds, 14, 15, 20 Mountain ash, 285 Mucous layer, 47 Mud, 102 Muir, John, 141 Multiple effect, 342, 423 Munkwitz, 145 Muscle, voluntary, 53 _Mycoderma_, 14, 20 _Myrica_, 250 _Myricaceæ_, 250 Myrobalans, 231, 280, 293 -- crusher, 322 -- extraction, 345 _Myrtaceæ_, 284 _Myrtus_, 284

Nancite, 269 Naphthalene sulphonic acid, 29 Naphthols, 29 _Nauclea_, 277 Neb-neb, 289 Nesbitt’s bating process, 161 “Neutralising” chrome leathers, 216 Nihoul, 104 Nitrates and nitrites in water, 104 Nitrogen estimation, 70 “Non-tannins,” 310, 478, 483 Nucleolus, 11 Nucleus, 11

Oak-Bark, 222, 253 -- - -- extraction, 344 -- -twigs, 244 Oakwood, 254 -- extract, 222, 231, 256 Oaks, 252 _Œnothera_, 284 Oil, Arctic sperm, 371 -- birch, 372 -- black birch, 373 -- boiled linseed, 363 -- bottlenose, 371 -- castor, 353, 355, 360 -- cod-liver, 365 -- cottonseed, 364 -- egg-yolk, 393 -- from fats, 463 -- herring, 368 -- Japanese, 368 -- linseed, 362 -- menhaden, 367 -- neatsfoot, 358 -- olive, 359 -- porgie, 367 -- Russia, 372 -- sandalwood, 373 -- sardine, 368 -- sassafras, 373 -- seal, 367 -- sesamé, 364 -- shark-liver, 366 -- sod, 368, 380 -- sperm, 353, 371 -- Straits, 367 -- Three-crown, 367 -- Turkey-red, 361 -- vaseline, 375 -- whale, 367 -- wintergreen, 373 Oils and fats in currying, 384 -- blown, 355, 361 -- drying, 353 -- essential, 350, 372 -- fixed, 350 -- lubricating, 453 -- mineral, 374 -- non-drying, 353 -- resin, 376 -- volatile, 372 Oleic acid, 240, 354, 360 Oleine, 359 Oleostearine, 356, 359 _Onagraceæ_, 284 One-bath chrome process, 211 Organised ferments, 15 Origin of leather manufacture, 1 Osmotic pressure, 78 _Osyris_, 267 _Ovum_, development of, 46 Oxalates, 159 Oxalic acid, 155, 221 _Oxalideæ_, 280 _Oxalis_, 280 Oxynaphthoic acid, 30, 163 Ozokerit, 376

Paal, 57, 62, 66 Paessler, 56 Pairing, 407 Palmer, A. N., 167 Palmer, T., 176 Palmetto, 245 _Palmæ_, 248 Pancreatin, 172 _Panniculus adiposus_, 53 _Papilionaceæ_, 285 Paraffin, 375 Paraform, 31 Parapeptones, 66 _Parenchym_, 243 Parker, J. G., 162 Parker, C. E., 455 _Pars papillaris_, 51 “Partial” pressure, 76 Paypay, 293 Payne and Pullman, 137 Peaty waters, 106 _Penicillium_, 14 Pepsin, 171 Peptones, 60, 61, 62 Perching, 188 Perchromic acid, 200 Perkin, 250, 394 -- and Allen, 276 -- and Gunnell, 269 Permanent hardness, 100 _Persea_, 267 “Persians,” 235, 287, 299, 365 Phenol, 26 -- for deliming, 162 Phenols, 295 Phenolphthalein, 155 _Phloem_, 243 Phlobaphenes, 231 Phloroglucol, 295, 297 Phosphates, 159 _Phyllanthus_, 293 _Phyllocladus_, 248 Pickling, 23, 89, 187 Pigeon-dung, 178 Pilang, 290 _Pinus_, 246 Pipes, arrangement of, 436, 440 -- heat from, 432 _Piptadenia_, 293 _Pistacia_, 269, 272 Pits, construction of, 454 Plaster-cure of Indian kips, 39 Pleating, 407 _Plumbaginæ_, 268 _Podocarpus_, 248 Poison ivy, 274 _Polygalaceæ_, 269 Polygenetic colours, 399, 403 _Polygonaceæ_, 264 _Polygonum_, 266 Polysulphides, 165, 211 “Polysulphin,” 139 Pomegranate, 285 Poplars, 264 Popp, 172, 174 Porcelain, to mark, 304 Porter-Clark, 98 Potassium dichromate, 201 -- hydrate, 136 _Potentilla_, 285 Precipitation tanks, 468 Preller, 381 Press-leaches, 330 “Pricking,” 169 Primitive leather manufacture, 1, 73 Printing, 418 _Protaceæ_, 268 Procter, 203 Procter’s extractor, 306 _Prosopis_, 286 _Protea_, 268 Protocatechuic acid, 295 Protoplasm, 10 Pseudopodia, 11 _Pterocarpus_, 285 Puering, 8, 19, 152, 170, 233 Pulleys, 450 “pulling down,” 157 Pullman, 380 Pullman’s liming method, 137 Pulsometers, 459 Pumps, 457 _Punica_, 285 Putrefaction, 15, 19 Putrid soak, 113, 137 Putz, Dr., 69 Pyrogallol, 295 -- tannages, 234 -- tannins, 295 Pyroligneous acid, 154 Pyrrol, 62 _Pyrus_, 285

Quebracho, 231, 269, 277 -- wood, extraction, 347 Quercetin, 263 _Quercus_, 252 Quicklime, 122

Rabinowitsch, 17 Raw hide leather, 381 Realgar, 142 Reddening of leather by light, 405 “Reds,” 231, 297, 339 Reimer, 58, 64 Resin, 376 _Rete malpighi_, 47 Rhatany, 269 _Rhizophoraceæ_, 283 _Rhus_, 270 Riems, 381 Roans, 235 Rollet, 64 Rolling machines, 224 Roman leathers, 2 _Rosaceæ_, 285 Rosin, 376 Rounding, 151 _Rove_, 261 _Rubiaceæ_, 277 _Rumex_, 264 Rusma, 139 “Russia” leather, 251

_Sabal_, 248 _Saccharomyces_, 14, 20 Saccharomycetes, 15 Saddening, 398 _Salicaceæ_, 263 Salicylic acid, 28, 295 Saliva-corpuscles, 10 _Salix arenaria_, 238, 263 -- _caprea_, 239, 264 Salomon, 178 Salt, 22 -- and acids, action on gelatine, 88 -- -stains, 22, 38 Salts, action on hide, 84, 92 Salted hides, 109 Salting, 35 Sampling tanning materials, 301, 475 -- tool, 301 _Santalaceæ_, 267 Saponification, 351 Sappan-wood, 287 Saturated solutions, 77 _Saxifragaceæ_, 280 Schilling, 62 Schinia, 272 _Schinus_, 270 Schmeija mill, 318 Schulze, 178 Schultz, A., 203, 204 -- Jackson S., 112, 454, 456 Schutzenberger, 57 _Scilla_, 248 _Scorza rossa_, 248 Scouring, 384 -- machine, 384 Screening tanning materials, 323 Scudding, 180 Sea lavender, 268 Seagrave-Bevington dryer, 438 Seaside grape, 267 Seasonings, 418 Sebaceous glands, 48 Semiglutin, 60 Semipermeable membranes, 78 _Senna_, 288 _Septa_, 14 Septic tank, 472 Settling tanks, 468 Sewage, 467 -- purification, 468 Shafting, 448, 450 Shake-method, 312, 483 Shaving, 384 -- machine, 384, 386 -- mill, 323 Sheep-skins, 34 Shellac glaze, 401 Silent boiling jets, 334, 343 Silicic acid in water, 104 Silver fir, 246 Skens, 272 Skin, structure, 46 Skivers, alumed, 197 Skutch, 462 Slaking of lime, 122 Slocomb staking machine, 192 Sludge, 470 Smoked leathers, 2 Snakeweed, 266 Snoubar bark, 248 Soaking and washing, 7 -- of hides, 108 -- with caustic soda, 114 Soaps, 351 -- cold process, 352 Soap test, 94 Society of Arts, 234 Soda in water, 103 Sodium bisulphate, 155 -- carbonate, 139 -- hydrate, 136 -- silicate, 216 -- sulphate, 23, 41 -- sulphide, 114, 139 -- thiosulphate, 204, 213, 216 Sole-leather tanning, 220 Solid solution, 83, 396 -- state of matter, 74 Solubility of liquids, 76 Solution-pressure, 76, 78 Soluble phenyl, 28 _Sorbus_, 285 Souring, 410 Spent tan, 329, 464 -- tans, analysis, 480 Spermaceti, 371 Splitting, 384 Sprinkler, 446 -- -leach, 336 Spruce fir, 246 Spueing, 20, 353, 355, 390 Squill, 248 Staining, 415 -- dyes suitable for, 486, 491 Stains caused by hard water, 99 -- on sole-leather, 227 Staking, 188 -- machines, 192 Staling, 34 Stanhope, 98 _Statice_, 268 Steam-engine, 423, 433, 448 -- - -- indicator, 449 -- -pumps, 457 -- -traps, 442 Stearic acid, 351 Stearin, 351, 359 Stearine glaze, 401, 415 Stenhouse, 296 Sterilisation, 18 Stinco, 272 _Stippen_, 109 Stocking, 180 Stocks, 116 -- for unhairing, 145 Stone-cells, 245 -- pits, 454 Striking, 223 -- machine, 223 Stringy bark tree, 284 Structure of skin, 46 Stuffing, 386 -- drum, 388 Sturtevant dryer, 438 Sudoriferous glands, 49 Sugar-bush, 268 Sulphate of soda, 23 Sulphates in water, 104 Sulphide of sodium, 34, 132, 139, 165 Sulphides, 139 Sulphur dioxide, 23 -- in chrome-leather, 216 Sulphonated oils, 361 Sulphuric acid, 114, 154, 157, 410 Sulphurous acid, 23, 114, 338 Sumach, 234 -- Cape, 267 -- extraction, 347 -- French, 277 -- Sicilian, 270 -- Venetian, 276 Sumachs, American, 273 Sumaching, 410, 411 Supersaturated solutions, 77 Surface-tension, 76 Suspenders, 221, 227, 232 Suspension lime-pit, 128 Swan, 202 Sweat-glands, 49 -- -pit, 119 Sweating, 1, 19, 34, 119 Swedish glove-leather, 236, 238 Swelling, 82, 84

Tallow, 356 -- fish, 368 _Tamarix_, 272, 280 _Tamarisciniæ_, 280 Tamwood, 269 Tan as fuel, 464 -- -burning furnaces, 464 -- -press, 467 _Tanekahi_ bark, 248 Tanghadi bark, 287 Tank-waste, 141 Tannery, construction, 445 -- extension, 447 -- fire risks, 446, 452 -- selection of site, 444 Tannin colour-lakes, 397 -- materials, extraction, 305 -- -- sampling, 302 “Tanning matters,” 311, 478, 483 Tannins, 242, 294, 397 -- pathological, 298 -- physiological, 298 Tari pods, 286 Tartar emetic, 411 Tawing, 191, 196 Temperature, 422 -- in leaching, 343 Temporary hardness, 94, 154, 411 Tengah bark, 283 Teri pods, 286 _Terminalia_, 280 Terra japonica, 277 Thann tree, 282 Thermophilic bacteria, 17 Tinian pine, 249 Tintometer, 315, 479 Titanium, 185, 218, 411, 495 Tjamara laut, 249 Topping, 406 _Tormentilla_, 285 _Torula_, 14 “Total soluble” matter, 307, 477, 478 Treacle, 177 Tri-formol, 31 Trimble, 263 Trioxymethylene, 31 Trypsin, 171, 172 _Tsuga_, 246 Tub-leaches, 331 Tugwar, 293 Turkey oak, 255, 256 -- -red oil, 217, 240 Turwar bark, 235, 287 Turret-dryer, 439 Two-bath chrome process, 204, 213, 216 Tyrosin, 66

Unhairing, 7, 54, 143 -- machines, 144 Unorganised ferments, 15, 16 Used liquors, analysis, 480

Vacciniæ, 280 _Vaccinium_, 280 Vacuoles, 13 Vacuum-oven, 308 -- pans, 342 Valdivia leather, 267 Valonia, 222, 231, 258 -- extraction, 345, 346 Valve, 457 -- for liquor troughs, 333 Van Tieghem, 243 Vapour-pressure, 75, 421 Vaseline, 375 Vaughn fleshing machine, 145, 148 Vegetable-tanned leathers, 2, 3 Velocity of gaseous molecules, 75 Ventilation and heating, 429 -- downward, 440 Verbeek and Peckholdt, 310 Vibration, 452 Vitellin, 67 _Vitis_, 272 Von Höhnel, 242 -- Schroeder, 56, 129, 134

Wagner, 298 Warbles, 43 Ward, H. Marshall, 243 Wash-wheel, 108, 118, 180 -- -- for unhairing, 145 Washing of hides, 108, 111 Waste liquids, 467 Water, condensed, 442 -- hardness, 93 -- impurities, 93 -- oven, 308 -- raisers, 459 -- softening, 95, 101 Wattles, 290 Wax, bees-, 371 -- Brazilian, 372 -- carnauba, 372 -- Japan, 372 -- mineral, 374 -- paraffin, 375 Waxes, 350, 353, 370 -- liquid, 350, 353, 371 Weak grain, 108 Weighing for analysis, 304 _Weimannia_, 280 Weiske, 63 “Wet and dry bulb” thermometer, 426 “White bark,” 293 -- leathers, 197 -- or gelatinous fibres, 50 -- spruce, 247 Wichellow and Tebbutt, 241 Wild almond, 268 Williams’ patent crusher, 320 Willow-bark, 238 Willows, 263 Wilson, 223, 224, 440 Wind, 427, 439 Windbores, 459 Wood, J. T., 166, 171 Woolfat, 358 Woolly butt tree, 284 “Working,” 180

Xanthoproteic acid, 67

Yaryan evaporator, 339, 424 Yeast, 12 Yeasts, 15 Yellow fibres, 53, 69 Yolk of egg, 68 Yorkshire grease, 359 Youl, 231 Young hair, 144

Zinc chloride, 26 -- sulphate, 26, 159 Zollickoffer, 160 Zymases, 15, 16, 17, 61, 296

LONDON: PRINTED BY WILLIAM CLOWES AND SONS, LIMITED,

GREAT WINDMILL STREET, W., AND DUKE STREET, STAMFORD STREET, S.E.

Transcriber’s Notes

Inconsistent and unusual spelling, hyphenation, etc. (including in names and non-English words) have been retained, except as mentioned below.

The original work does not have a Fig. 17.

Page 199, (It must be distinctly understood ...: the closing bracket is missing in the source document.

Page 223: ... tool of triangular section shown in Fig. 29: the reference should possibly be to Fig. 27 (or 30).

Page 267, kruppelboom: should possibly read kreupelboom.

Changes made:

Footnotes, illustrations, and tables have been moved outside text paragraphs.

The following phrases have been standardised: C. T. bate and C.T. bate to C.T. bate (cole-tar); c.c. and cc. to c.c. (cubic centimetre); Liége and Liège to Liège. Pullman and Pullmans to Pullman; Huxham and Brown and Huxham and Browns to Huxham and Browns; Kjehldahl and Kjeldahl to Kjeldahl; Körner and Koerner to Koerner.

Where useful for clarity’s sake, Ibid. in literature references has been replaced with the actual (abbreviated) title.

Some obvious minor typographical errors have been corrected silently; accents in French and German words have not been corrected or added.

Page 40: In the re-renewal ... changed to In the renewal ... Page 64: Chrondrin changed to Chondrin Page 74: Die Natur und Wesen ... changed to Natur und Wesen ... Page 139: Na₂S,9OH₂ changed to Na₂S·9OH₂ Page 248: footnote anchor removed from after ... by cork lamellæ (there is no footnote in the original work). Page 252: ... and the more colouring matter is contained ... changed to ... the more colouring matter is contained ... Page 253: ... and the better the bark changed to ... the better the bark Page 272: Ailantus gladulosa changed to Ailantus glandulosa Page 310: Verbeck changed to Verbeek Page 329: ... is shown in Fig. 86 changed to ... is shown in Fig. 77 Page 361: Benedict changed to Benedikt Page 400: Claus and Ree changed to Claus and Rée Page 429: 44°3 F. changed to 44·3° F. Page 451: kilos per cm² × 14·22 = lb. per inch changed to kilos per cm² × 14·22 = lb. per inch² Page 486: Acid green B.B. changed to Acid green BB. Page 501: Blue-backing changed to Bluebacking Page 507: Oxalic acid, page number 155 corrected Page 508: Pay-pay changed to Paypay; Phylocladus changed to Phyllocladus; Protacæ changed to Protaceæ Page 509: Schutzenberger changed to Schützenberger Page 512, Zymases: page numbers 17, 61, 296 inserted Index: some entries moved to their proper place.